Hydrophilic polymer treatment of an activated polymeric material and use thereof

ABSTRACT

A method of modifying a polymeric material which comprises the steps of activation-treatment and a hydrophilic polymer-treatment, or comprises the steps of activation-treatment, a hydrophilic polymer-treatment, and monomer grafting in this order, or comprises the step of a solvent-treatment followed by these steps. Thus, the polymeric material, e.g., polyolefin, is improved in hydrophilicity, adhesion, etc. without lowering the practical strength thereof. The polymeric material thus improved in adhesion and other properties can be used in many applications where water absorption and adhesion are required, such as an absorption material, e.g., a wiping/cleansing material, a water retention material, a material for microorganism culture media, a separator for batteries (or cells), a synthetic paper, a filter medium, a textile product for clothing, a medical/sanitary/cosmetic supply, and reinforcing fibers for composite materials.

TECHNICAL FIELD

The present invention relates to a method of modifying the property of apolymeric material. More particularly, the invention relates to a methodto improve the properties such as water absorption and adhesion, etc. ofa polymeric material without lowering the practical strength of thematerial.

BACKGROUND ART

Because polyolefins such as polypropylene, polyethylene, etc. haveexcellent properties of light weight, large strength, good chemicalresistance, etc., they are extensively used for films, non-wovenfabrics, molded materials for automobile components and members ofelectrical apparatus, etc. On the other hand, polyolefin materials havea small polarity and a high crystallinity, which are derived from itschemical structure, thus they have a small hydrophilic property and adifficulty in chemical modification. Various surface activationtreatments such as ozone treatment, plasma treatment, ultraviolet lightirradiation, high voltage electric discharge, corona discharge, etc.have been carried out to improve the hydrophilic property and adhesiveproperty of polyolefin materials. However, even if any method of them isemployed to treat a polyolefin material, we cannot obtain an effectiveresult that the treated material absorbs water as much as several timesthe weight of original material.

Various kinds of treatments have been proposed in order to improve theproperty of polymeric materials such as polypropylene, etc. Forexamples, the ozone oxidation treatment was examined to improve theproperty of metal plating, painting and adhesion (Japanese Laid-OpenPatent Publication No. H3-103448 (1991)). However, when only the ozonetreatment is employed to improve the property of the material, it needsvery strict conditions which cause the lowering of the mechanicalstrength; this makes a problem that the treatment is not practical.Furthermore, it is impossible to give a large water absorption propertyto the material only by the ozone treatment.

Furthermore, it was proposed that vinyl monomers containing ester bondswere grafted to non-woven fabrics made of polyolefin and then, the esterbonds were hydrolyzed to form acid groups giving a hydrophilic propertyand an ion-exchange property (Japanese Laid-Open Patent Publication No.H11-7937 (1999)). However, the grafting of vinyl monomers to polyolefinto give a large hydrophilic property is not easily carried out by theproposed method. Still more, the method needs the hydrolysis treatmentafter the grafting, which causes a laborious problem.

On the other hand, a method to improve a hydrophilic property ofnon-woven fabrics made of polyolefin fibers by the treatment withhydrophilic resin in the presence of a persulfate was proposed (JapaneseLaid-Open Patent Publication No. H11-67183 (1999)). Although this methodgave practically a hydrophilic property to non-woven fabrics, thehydrophilic property is not durable in use. In addition, this method wasnot applicable for the improvement of hydrophilic property and adhesionproperty of films and molding materials except non-woven fabrics. Forinstance, the hydrophilicity given by this method is considerably lostby washing with a hot detergent solution.

It is known that a method to improve a hydrophilic property of non-wovenfabrics by coating them with polyvinyl alcohol (Japanese Laid-OpenPatent Publication No. H1-248460 (1989)). Although the hydrophilicproperty of the treated non-woven fabrics is high, its durability isvery low because the treatment is only coating. In addition, the coatednon-woven fabrics give a disadvantage in that when they are used asbattery separators, they shrink and cause short-circuiting in thebatteries.

The present inventor proposed a method to improve the surface property,or especially, the dyeability of polymeric materials, which is composedof activation treatment of the surface of polymeric materials, monomergrafting such as acryl amide, etc. on them and Hofmann rearrangement ofthe amide groups in grafts (Japanese Laid-Open Patent Publication No.H8-109228 (1997)). Although this method is available for improving thehydrophilic property of some polymeric materials, the kind of availablepolymeric materials is limited.

The present invention provides a method for improving a durable waterabsorption property, a hydrophilic property and an adhesion, etc. for apolymeric material without lowering the practical strength. The presentinvention also provides medical/sanitary/cosmetic supplies; disposablediapers, sanitary or other napkins, bandages, gauze and disinfectantsand various water-absorption materials for cleaning, cleanser pack,etc., water retention materials useful for agriculture/greening in drydistricts, materials for microorganism culture media, synthetic paper,filter media, battery separators with alkali/acid proofing, members ofwriting materials with an excellent absorption property of water-solubleink, wiping/cleansing materials, orthodontic brackets, medical materials(artificial organs, artificial joints, medical tubes and the othermolded materials with string or plate forms), polymeric materials withimproved adhesive property and polymeric materials for composites.

DISCLOSURE OF INVENTION

The present inventor investigated the method for improving the propertyof polymeric materials such as a water adsorption property, ahydrophilic property, and an adhesion property, etc. and discovered thata combination of a solvent treatment, an activation treatment, ahydrophilic polymer treatment and a monomer grafting is effective forthe improvement, and completed the present invention.

A first aspect of the present invention relates to the method forimproving polymeric materials by (1) the step of activation-treatmentand (2) the step of a hydrophilic polymer-treatment in this order.

A second aspect of the present invention relates to the method toimprove polymeric materials by (1) the step of activation-treatment and(2) the step of a hydrophilic polymer-treatment and (3) the step ofmonomer grafting in this order.

A third aspect of the present invention relates to the method to improvepolymeric materials by (1) the step of a solvent-treatment, (2) the stepof activation-treatment and (3) the step of a hydrophilicpolymer-treatment in this order.

A fourth aspect of the present invention relates to the method toimprove polymeric materials by (1) the step of a solvent-treatment, (2)the step of activation-treatment, (3) the step of a hydrophilic polymertreatment and (4) the step of monomer grafting in this order.

The present invention also relates to the products prepared from thepolymeric materials improved by the above methods; a water absorptionmaterial, a water retention material, a material for microorganismculture media, a synthetic paper, a filter medium, a battery separator,a member of writing materials (members made of polymer used for variouskinds of pens with water-soluble ink, felt pens, brush pens, fountainpens and ball-point pens, etc.), a wiping/cleansing cloth, a disposalmedical/sanitary/cosmetic supply (a diaper, a sanitary napkin, abandage, a gauze, the other medical/sanitary supply and various cosmeticsupplies for cleaning/cleansing pack), a material improved in adhesionproperty, an orthodontic bracket, a medical material (an artificialorgan, an artificial joint, a medical tube and the other moldingmaterial of tube, string or plate), etc.

The present invention will be described in more detail. (Polymericmaterials)

Polymeric materials used in the present invention include the polymermaterial contained in each of a single polymer or a mixture of syntheticor natural polymers, a modified single polymer or polymer mixture, amaterial prepared by mixing or conjugating the polymers with glass,metal and carbon fiber, etc.

Both thermoplastic polymers and thermosetting polymers are used assynthetic polymers. Various methods for the preparation of thesepolymers are exemplified, and all polymers prepared by these methods canbe used. For example, the following polymers are available; (1) polymersmade by an addition polymerization; homopolymers or copolymers preparedby the polymerization of a single kind of monomer or a mixture ofmonomers selected from olefins, vinyl compounds except olefins,vinylidene compounds, the other compounds with C═C double bonds, (2)polymers made by polycondensation; a polyester and a polyamide, etc. ortheir mixture or modified polymers, (3) polymers made by additionpolycondensation; phenol resin (containing Kynol (commercial name ofJapan Kynol Co., Ltd.), urea resin, melamine resin, xylene resin, ortheir mixture or modified polymers, (4) polymers prepared bypolyaddition; polyurethane, polyurea, and these mixture or modifiedpolymers, (5) polymers prepared by the ring-opening polymerization; ahomopolymer or a copolymer prepared by cyclopropane, ethylene oxide,propylene oxide, lactone and lactam, and these mixtures or modifiedpolymers, (6) cyclic polymers; polymers prepared by the polymerizationof divinyl compounds (e.g., 1,4-pentadiene) or diyne compounds (e.g.1,6-heptadiyne) and these mixture or chemically modified polymers, (7)polymers prepared by isomeric polymerization; e.g., alternativecopolymer of ethylene and isobutene, (8) polymers prepared by theelectrolytic polymerization; a homopolymer or a copolymer prepared bypyrrole, aniline and acetylene, etc. and their mixture or chemicallymodified polymers, (9) polymers made of aldehydes and ketones, (10)poly(ethersulfone) and (11) polypeptides.

A single material or a mixture of cellulose, proteins andpolysaccharides or these derivatives, etc. are given as naturalpolymers.

In the present invention, the polymers made by an additionpolymerization described above are preferably used. Monomers used in anaddition polymerization are not specially limited. A homopolymer or acopolymer of α-olefins such as ethylene, propylene, butene-1, pentene-1,hexene-1,4-methylpentene-1, octene-1, etc. are used.

In the present invention, vinyl compounds except olefins give thecompounds with vinyl groups. For instance, the following compounds aregiven; vinyl chloride, styrene, acrylic acid, methacrylic acid, estersof acrylic or methacrylic acids, vinyl acetate, vinyl ethers, vinylcarbazole, and acrylonitrile, etc.

As compounds except olefins compounds containing vinylidene groups;vinilidene chloride, vinilidene fluoride and isobutylene areexemplified.

As the compounds with carbon-carbon double bonds except olefins, vinylcompounds and vinilidene compounds, the following compounds are given;maleic anhydride, pyromellitic dianhydride, 2-butene acid,tetrafluoroethylene, chlorotrifuluoro-ethylene, etc. and compounds withtwo or more vinyl groups, for instance, butadiene, isoprene andchloroprene, etc.

As preferable polymers made by the addition polymerization, homopolymersor copolymers of two or more monomers selected from these monomers or amixture of these polymers can be suitably used. Especially preferableaddition polymers are polyethylene, a copolymer of ethylene and theother α-olefin, polypropylene, a copolymer of propylene and the otherα-olefin. These copolymers represent both of random copolymers and blockcopolymers. As the present invention is effective for the improvement ofthe hydrophilic property of polyolefins, which is especially difficultfor a chemical treatment, polyolefins are preferably used.

As polymeric materials other than polyolefins, homopolymers orcopolymers of monomers selected from vinyl compounds, vinylidenecompounds or compounds with carbon-carbon double bonds;poly(methacrylate)s, poly(acrylate)s, polystyrene, polytetrafluoroethylene, copolymers containing acrylonitrile (acrylic fiberand its molded product and ABS resin, etc.) and copolymers containingbutadiene (synthetic rubber), etc., polyamides (contain-ing nylon andaliphatic or aromatic polyamides), polyesters (containing polyethyleneterephthalate and aliphatic or all-aromatic polyesters), polycarbonate,polyurethane, polybenzoate, polyethersulfone, a carbon material such ascarbon fiber, etc., various synthetic rubbers, wool, silk, etc. arepreferably used.

As the polymers except the above ones, the following polymers arepreferably used; poly(phenol) (commercial name, Kynol),poly(alkyl-p-hydroxybenzoate), polyimide, poly(benzimidazole),poly-(p-phenylene benzobisthiazole), poly-(p-phenylene benzbisoxazole),poly(benzothiazole), poly(benzoxazole), and the following fibers arepreferably used; cotton, flax, hemp, ramie, jute, and other vegetablefibers, animal hair fibers except wool, cellulose acetate, regeneratedcellulose (rayon, cupra, polynosic, etc.), vinylon, a copolymer ofvinylalcohol and vinylchloride (polychlal; commercial name, Cordera) andcasein fiber. In addition, mixtures or composites of these polymericmaterials are preferably available.

The polymeric materials are not limited to the above exemplified onesbut any of other polymers may be used for the present invention.

It is possible to improve the polymeric materials containing antistaticagents, stabilizers, nucleation agents, flame retardants, foaming agentsand various additives which are usually added in polymeric materials bythe present invention.

In the present invention, the form of polymeric materials to be improvedis not limited. For instance, each of fiber, a woven fabric, a non-wovenfabric, a cloth, a plate, a film, a tube, a rod, a hollow container, acase, a foamed material and a laminate is available. Especially, thewater absorption property of fibers, woven fabrics, non-woven fabrics,cloth, films, and sheets can be easily improved. Porous films and sheetsprepared for filtration mediums or synthetic papers are easily improvedin a durable water absorption property. In addition, by improvingmembers/parts of materials molded previously in a desired form, thepolymeric materials which had not been used are enabled to be useful.For instance, when members of writing materials (ink holders, brushes ofbrush pens, felt-pens, autograph pens, ink-collector, etc.) made ofpolyolefins, polyesters and ABS resin are treated by the present method,the obtained members/parts become wettable with water-soluble ink andthe performance of the writing materials can be advanced. When the otherplastic materials (volts, nuts, chains, parts of electronics, caps,covers, etc.) are treated by the present method, their wettability andadhesion property are improved and the electrification is decreased.

Among fibers and fiber products, for instance, a polyolefin fiber, apolyester fiber, an acrylic fiber, a polyurethane fiber, a polyamidefiber such as nylon and polyaramide, a polyvinyl chloride fiber, acarbon fiber, silk, wool, etc. or woven fabrics and non-woven fabrics ofthese fibers are preferably used. Each form of fibers is available; asingle kind of fiber, a mixture of two or more kinds of fibers, a mixedspinning fiber and a conjugate fiber (a sheath-core type fiber, aside-by-side aligned fiber, a multi-core fiber, an island-in the-seatype (archipelago type) and a hollow-segment-pie fiber, etc.).

(Activation Treatment Process)

In the present invention, the activation treatment process is tointroduce functional groups containing oxygen or nitrogen, etc. orunsaturated bonds into the surface of the polymeric materials by varioustreatments such as ozone treatment, ultraviolet light irradiationtreatment, discharging process, etc. It is not necessary to put vinylmonomers or other organic compounds in this process.

The extent of the activation treatment is not especially limited; itdepends on the purpose of the treatment. An infrared spectroscopy isemployed to see the extent of the activation treatment. For example, aratio of the absorbance due to carbonyl groups introduced in materialsto that due to the crystalline region which is not changed by thetreatment is estimated by the base line method and it is used to see theextent of the oxidation by the activation treatment.

In the present invention, observing the absorbance due to carbonylgroups before and after the treatment, the extent that a trace of theformation of carbonyl groups is made sure, which suggests an oxidation,is enough and preferable for the activation treatment. For instance, inthe case of polypropylene, it is preferable that the ratio of theabsorbance at around 1710 cm⁻¹ due to the carbonyl groups introduced inthe polymer to the absorbance at around 973 cm⁻¹ due to the methylgroups unchanged in the crystalline region is about 0.2 or less.

It is preferable that the polymeric materials are washed withappropriate solvents to remove the impurities before the activationtreatment. For instance, polyolefins, polyvinyl chloride andpolyvinylidene chloride, etc. are preferably washed with methanol andtoluene. Cellulose acetate, nylons, polyesters, polystyrene, acrylicresin, polyvinyl acetate, polycarbonate, polyurethane, etc. arepreferably washed with alcohols (methanol or ethanol). It is preferablethat cellulose materials such as cotton, hemp, rayon, cuprammoniumrayon, etc. are washed with alcohols after washing with detergents.

As a method of activation treatments, each of ozone treatment, plasmatreatment, ultra-violet right irradiation treatment, high voltageelectric discharge treatment and corona discharge treatment areavailable.

(Ozone Treatment)

The ozone treatment is to carry out a chemical reaction, mainlyoxidation of the surface of polymeric materials with ozone moleculesupon contact with ozone in order to improve the polymeric materials.

The ozone treatment is carried out by exposing polymeric materials toozone. Any methods of ozone treatment are available; for instance, toput a polymeric material under the atmosphere of ozone for a given timeor to put a polymeric material in the stream of ozone, etc.

Ozone is produced by passing air, oxygen, or gas containing oxygen suchas oxygen-added air through an ozone generator. The ozone treatment iscarried out by introducing the obtained gas containing ozone into areaction vessel or a container in which a polymeric material isinvolved. The conditions of ozone treatment such as a concentration ofozone in a gas containing ozone, an exposure time and temperature, etc.are appropriately determined considering a kind and form of a polymericmaterial and the aim of the surface improvement. Usually, an ozoneconcentration from 0.1 to 200 mg/l, a temperature from 10 to 80° C. anda reaction time from 1 minute to 10 hours are applicable. For example,the treatment with the ozone concentration from 10 to 40 g/m³ and a timefrom about 10 to 30 minutes at room temperature is available for thetreatment of polypropylene and polyvinyl chloride fibers. When apolymeric material is a film, a treatment with an ozone concentration of10 to 80 g/m³ and the time from about 20 minutes to 3 hours isavailable. When air is used instead of oxygen, the ozone concentrationbecomes about a half of that with oxygen.

It is considered that hydroperoxide groups (—O—OH), etc. are formed andsome of them are changed to hydroxide groups and carbonyl groups on thesurface of a polymeric material by the reaction, mainly oxidation, withozone treatment.

(Plasma Treatment)

A plasma treatment is carried out to introduce functional groupscontaining oxygen, nitrogen, etc. to the surface of materials; apolymeric material is put in a vessel containing a gas such as argon,neon, helium, nitrogen, carbon dioxide, oxygen and air, etc. and it isexposed to the plasma generated by a glow discharge. It is consideredthat radicals are generated on the surface of the polymeric material bythe attack of the plasma. Subsequently, the radicals are exposed to airand reacted with oxygen to form carboxylic groups, carbonyl groups andamino groups, etc. on the surface of the polymeric material. The plasmatreatment under a low pressure of nitrogen, oxygen or air can producefunctional groups directly in the polymeric material.

Methods of the electric discharge are classified in (1) a direct currentdischarge, (2) a radio-wave discharge, and (3) a microwave discharge.

(Ultraviolet Radiation Treatment)

Ultraviolet radiation treatment is a method to irradiate an ultraviolet(UV) light to the surface of polymeric materials. Low-pressure mercurylamps, high-pressure mercury lamps, super high-pressure mercury lamps,xenon lamps and metal halide lamps are employed as a UV light source. Itis effective that a polymeric material is treated with a solvent whichcan absorb UV light before the UV irradiation. Although any wave lengthof UV light is available, that of around 360 nm is preferable todecrease the deterioration of the material. The following is considered.When a UV light is irradiated to a polymeric material, a part of thelight is absorbed by the chemical structure such as double bonds, etc.in the surface of the polymeric material and some chemical bonds arebroken to produce radicals by the absorbed energy. The resultingradicals are considered to produce carboxylic groups or carbonyl groupsvia peroxides by the bonding of oxygen in air.

(High Voltage Electric Discharge Treatment)

A high voltage electric discharge treatment is as follows. A polymericmaterial is put on a belt conveyor roller equipped in a tunnel-shapedinstrument and the material is carried by the belt. A high voltage suchas several hundred thousands volts is put between a lot of electrodesattached to the inner wall of the instrument, which makes an electricdischarge in air. It is considered that the electric discharge activatesthe oxygen in air and the surface of the material, and the oxygenincorporated into the material forms polar groups in the polymericmaterial.

(Corona Discharge Treatment)

A corona discharge treatment is as follows. A high voltage of severalthousands volts is given between a grounded metal roller andknife-shaped electrodes which are aligned in several millimeterintervals to the metal roller. A polymeric material is passed throughthe space between these electrodes where the corona discharge isgenerating. This method is suitable for films or thin materials.

The methods except the ozone treatment are based on an energyirradiation. When a polymeric material has a part which makes a shadowfor the irradiation, some techniques are necessary to treat the part bythe irradiation. Therefore, the ozone treatment is preferable for thetreatment of materials such as a non-woven fabric and a fiber-assembledmaterial which gives shadow parts derived from the material's structure.In addition, the ozone treatment is economical and preferable because ofthe inexpensive facility

A polymeric material activated by the ozone treatment, etc. issubsequently treated by a hydrophilic polymer treatment. Further more,the material treated by a hydrophilic polymer is treated by a monomergrafting in the Aspects 2 and 4 of the present invention.

(Solvent Treatment)

In order to make the activation treatment more effective, “solventtreatment” is preferably carried out before the activation treatment.

The solvent treatment is to dip a polymer material in a solvent whichhas a poor solubility of it under the condition that the material is notdissolved in it. A polymeric material is dipped in such a solvent forabout 1 minute to 60 minutes at a temperature range of room temperatureto about 60° C., and the material gives a weight increase of 0.2 to 10%of the original weight without any deformation. This process can becompleted by drying the material quickly after dipping in the solvent.The solvent treatment is not always necessary when the polymericmaterial is a non-woven fabric or fibers. But, this treatment is veryeffective for the treatment of a material with a small surface area suchas films and plates, or for a material containing a considerable amountof antioxidants or other additives. In the case of polypropylene, thematerial is immersed in a liquid for a solvent treatment (such astoluene, xylene, decalin, tetralin, cyclohexane, etc.) for 1 to 30minutes in the range of room temperature to 50° C., and the surface ofthe material is dried. Subsequent treatment should be carried out soonafter the solvent treatment. As a liquid for the solvent treatment ofpolyethylene, decalin, tetralin, xylene, and 1-chloro-naphthalene, etc.are effective. For each of the other polymers, a combination of asolvent and a temperature which gives no solubility of the polymershould be examined.

For example, a non-woven fabric made of polyolefin fiber with a circlecross section of a diameter of about 5 to 10 μm is immersed into toluenefor 2 minutes at room temperature, and is squeezed, and remainingtoluene is removed by a centrifugation. Then, the material is dried byan electric fan; when the toluene on the surface of the material seemedto be evaporated apparently, the solvent treatment is finished. In thecase of polyolefin films or plates and the other molded materials, theyare immersed in toluene for 10 to 30 minutes at 50° C., squeezed asdescribed above, and dried. In these cases, the weight increase is fromabout 1% to 5%.

(Hydrophilic Polymer)

In the present invention, “hydrophilic polymers” representswater-soluble polymers or polymers which are not soluble in water buthave a hydrophilic property. Specific examples of polymers are asfollows; poly(vinyl alcohol), sodium carboxymethyl cellulose,ethylene-vinyl alcohol copolymer, poly(hydroxyethyl methacrylate),poly(α-hydroxy vinyl alcohol), poly(acrylic acid), poly(α-hydroxyacrylic acid), poly(vinyl pyrrolidone), poly(alkylene glycol)s such aspoly(ethylene glycol) and poly(propylene glycol), starch such as potatostarch, corn starch, wheat starch, etc., glucomannan, silk fibroin, silksericin, agar, gelatin, egg white, sodium arginate, etc. Thesesulfonates can also be available.

(Hydrophilic Polymer Treatment)

It is preferable that the hydrophilic polymer treatment of a polymericmaterial made by the activation treatment is carried out in the presenceof catalysts or initiators (generically, they are called “initiators”,and used similarly in the monomer grafting).

The following initiators are exemplified; peroxides (benzoyl peroxide,t-butylhydroxy peroxide, di-t-butylhydroxy peroxide, etc.), ceriumammonium nitrate (IV), persulfates (potassium persulfate, ammoniumpersulfate, etc.), oxidation-reduction initiators (oxidants;persulfates, hydrogen peroxide, hydroperoxide, etc. and inorganicreductants; copper salts, iron salts, sodium hydrogen sulfite, sodiumthiosulfate, etc. or organic reductants; alcohols, amines, oxalic acid,etc. and these mixture, and oxidants; hydrogen peroxide, etc. andinorganic reductants; copper salts, iron salts, sodium hydrogen sulfite,sodium thiosulfate, etc., or organic reductants; dialkyl peroxide,diacyl peroxides, etc. and reductants; tertiary amines, naphthenates,mercaptans, organometallic compounds (triethyl aluminium, triethylboron, etc. and these mixture), the other usual initiators of radicalpolymerization, etc.

In the hydrophilic polymer treatment process, it is preferable to use ahydrophilic polymer in the solution state. A water-soluble polymer isused as an aqueous solution. When a hydrophilic polymer is not solubleeasily in water, it can be used as a solution in an adequate solvent.The use of water-soluble polymers is explained below.

When a treatment with a water-soluble polymer is carried out in theabsence of an initiator, a polymeric material finished by the activationtreatment is put in an aqueous solution of the water-soluble polymer.

When a treatment with a water-soluble polymer is carried out in thepresence of an initiator, first, an aqueous solution of thewater-soluble polymer is prepared. Then, if the initiator iswater-soluble, a given amount of it is dissolved in the aqueous solutionof the water-soluble polymer. If the initiator is not dissolved inwater, it is dissolved in an organic solvent such as alcohols or acetonewhich are miscible with water, and then, the solution is added in theaqueous solution of the water-soluble polymer. Then, a polymericmaterial finished by the activation treatment is put in the solution ofthe water-soluble polymer and the initiator. The inner atmosphere of thereaction vessel is desirable to be substituted with nitrogen gas, butthe nitrogen atmosphere is not always necessary for a usual treatment.

The temperature is not limited for the treatment with a water-solublepolymer and an initiator, usually, the temperature of 10°C. to 80° C. isavailable, but that of 60° C. to 90° C. is more preferable. Thetreatment for a long period of time (e.g.,.about 12 hours) at a hightemperature is preferably carried out in order to obtain a durablehydrophilicity of a polymeric material. A characteristic of the presentinvention is as follows. Even when the amount of a hydrophilic polymerbound to a polymeric material in the hydrophilic polymer treatment istoo small to be analyzed by usual analytical methods, a hydrophilicityof the polymeric material can be effectively improved by the presentinvention. Besides, as a ratio of a surface area of a polymeric materialdepends on the kind of the material, for instance, a percentage ofweight increase in a treated material is largely dependent on eachmaterial. As a molded polymeric material has a small specific surfacearea, even when the percentage of the weight increase in the treatedmaterial becomes a very small value less than 1 wt %, an effectivemodification can be obtained. In the case of thin films, the percentageof the weight increase in the treated material becomes larger ascompared with a thick molded product. In the treatment of a materialwith a large specific surface area such as a non-woven fabric, thematerial of a weight increase less than 5 wt % gives an excellentimprovement in the hydrophilicity. However, the present invention is notlimited by these values.

(Monomer Grafting Treatment)

In the present invention, the monomers for grafting are desirable tohave at least one carbon-carbon double bond, for instance, vinylcompounds or similar compounds to them are preferable, although theother monomers which polymerize are available. Hydrophilic monomers arepreferable for the present treatment. As hydrophilic monomers, at leasta single monomer or a mixture of monomers selected from the followingmonomers are preferably used; acrylic acid, methacrylic acid, vinylacetate, 2-butene acid, ethylene sulfonic acid, hydroxyalkyl acrylate,hydroxyalkyl methacrylate, acryl amide, vinyl pyridine, vinylpyrrolidone, vinyl carbazole, maleic anhydride and pyromelliticdianhydride. In the present invention, the use of acrylic acid ormethacrylic acid is especially desirable to obtain a polymeric materialwith a chemical resistance and a durable water absorption property.

It is a characteristic feature of the present invention that even if aslight amount of hydrophilic polymer is bound to a polymeric material,an effective improvement in the hydrophilic property of the material canbe obtained. As mentioned above, an effective hydrophilicity is improvedfor a thick molded product even when a weight increase in a polymericmaterial by grafting is a value much less than 1 wt %. In the treatmentof a film material, the weight increase by grafting is more than that ofa thick material. In the grafting of a non-woven fabric, the weightincrease less than 5 wt % gives a good hydrophilicity. However, thepresent invention is not limited by these values.

In addition, as monomers with low hydrophilicity such as vinyl monomerse.g., esters of acrylic acids, esters of methacrylic acids, vinylacetate, styrene, etc. can also be used. The use of only hydrophilicmonomers is preferable, but, sometimes, the use of a mixture of ahydrophilic monomer and a low hydrophilic monomer increases thepercentage of grafting and as a result, the hydrophilic monomer residuesin the graft can improve a hydrophilicity of the treated polymermaterial.

It is desirable that a monomer grafting to a polymer material is made bythe heating or the UV irradiation in the presence of initiators. Aninitiator can be selected from those used in “the hydrophilic polymertreatment”. When acrylic acid is used as a monomer, a water-solubleinitiator such as cerium ammonium nitrate (IV) or potassium persulfateis preferably used. A water-insoluble initiator such as benzoyl peroxideor AIBN is first dissolved in methanol or acetone and the solution ismixed with water. The final solution was used for the treatment. In thegrafting by a UV irradiation, a photo-sensitizer such as benzophenoneand hydrogen peroxide can be used instead of the initiators mentionedabove.

A grafting of monomers is carried out as follows. First, when awater-soluble initiator is used, the amount necessary for the treatmentis dissolved in water. If a water-insoluble initiator is used, it isdissolved in an organic solvent such as alcohols and acetone which ismiscible in water, and the solution was mixed with an appropriate amountof water, as taking care the precipitation of the initiator. The mixingratio of water to an organic solvent is not especially limited. Forinstance, a volume ratio of water/acetone=2/3 is preferable in a mixtureof water and acetone, and in a mixture of water and methanol, a volumeratio of water/methanol=1/1. Each of a material finished by anactivation treatment and a hydrophilic polymer treatment, and a materialfinished by a solvent treatment, an activation treatment and ahydrophilic polymer treatment is added in a solution of an initiator,and then a monomer is added in the mixture. It is desirable that thereaction vessel is under a nitrogen atmosphere, but the presenttreatment can be made under a usual air atmosphere for convenience. Athermal polymerization is carried out by setting a reaction mixture in athermostatted bath for a given time at a given temperature. For example,it is set for 30 minutes to 6 hours at 80° C. When a polymer material isnot sunk in a reaction mixture, it is desirable that the material issunk in the reaction mixture by putting an appropriate glass plate orvessel on it. On the other hand, in the case of a photo-polymerization,a Pyrex glass-made reaction vessel involving a reaction mixture isirradiated by an UV light for 30 minutes to 6 hours at 30° C. Various UVlamps are available, for instance, a high pressure mercury lamp, H400Pproduced by Toshiba Co., Ltd. is preferably used. UV light of about 360nm monochromated by a filter is applicable, but a whole range of UVlight from a UV lamp can also be used. A preferable distance between areaction vessel and a light source is from 10 cm to 30 cm. When apolymer material is not sunk in a reaction mixture, an appropriate glassplate or vessel is put on it for sinking the material in the reactionmixture.

When a reaction is finished, a polymeric material is taken out of thereaction mixture and is washed with water or an aqueous detergentsolution, rinsed well with water and dried. An example of a typicalmixing of the reactants is given as follows; a polymeric material 40-80g, an initiator 0.10-1.0 g and a solvent (mainly, water) 400 ml-800 ml.

As an example of a monomer mixture including a hydrophilic monomer, amixture of acrylic acid 8 volume and methyl methacrylate 2 volume isapplicable. When vinyl acetate or styrene is used, a hydrolysis or asulfonation should be carried out to improve the hydrophilicity afterthe grafting.

(Applications)

Properties such as hydrophilicity, water absorption property, waterretention property, adhesion property and chemical resistance, etc. areextremely improved in a polymeric material treated by the presentinvention. The polymeric materials improved by the present invention canbe used for many applications because of their characteristicproperties. As an adhesion property of a polymeric material is improved,for example, it can be bonded to paper, wood, metal, etc. with generaladhesives such as starch, poly(vinyl acetate), epoxy resin, andpoly(cyanoacrylate), etc. The present invention is applicable formaterials which are necessary for an adhesion property. Furthermore, thepresent invention is effective for the improvement of polyolefins suchas polypropylene and polyethylene whose improvement is known to bedifficult and other many kinds of polymeric materials. The waterabsorption property of a non-woven fabric of a polyolefin or that of amixture of a polyolefin and another polymer can be improved to givewater absorption of 7 to 10 times as much as the original weight. Inaddition, the improved materials give a good adhesion property andresistances to alkalis, acids and oxidation.

Several applications are described below, but still other applicationsare also possible.

(1) Battery Separators

The polymer materials improved by the method of the present invention,especially non-woven fabrics of polyolefins such as polypropylene andpolyethylene or non-woven fabrics of a mixture of polyolefins and theother polymers are very suitable for battery separators because theygive excellent properties in water absorption, adhesion property,resistances to alkalis, acids and oxidation. They give a waterabsorption ability of 7 to 10 times as much as the original weight and agood absorption ability of electrolytic solutions.

(Alkali Battery Separators)

As alkali battery separators are excellent for a charging-dischargingproperty, an overcharge-overdischarge property and have a long life-timeand a repetitive use, they are extensively used in a lot of electronicswhich need a small size and light weight. The battery with highercapacity is expected. These characteristics of the alkali batterylargely depend on the property of the battery separator. The followingrequirements are desirable for alkali battery separators; an affinity toelectrolytic solutions (alkali solutions), a large liquid-absorptionrate, a good liquid-retention ability, resistances to alkalis and acidswhich are durable for the repetitive charge/discharge process, anelectric insulation to prevent a short-circuiting, a low electricresistance when they absorb electrolytic solutions, a good permeabilityfor passing gas and ions released in batteries, a thin size suitable forsmall batteries, a uniform thickness, and a high tensile strength, etc.Non-woven fabrics of polyolefins improved in hydrophilic property andresistances to alkalis and acids are preferable for battery separatorssatisfying these requirements.

(Lead Storage Battery Separators)

An application for a lead storage battery is explained below.

Lead storage batteries are extensively used for cars and machinesbecause they have a good charge/discharge property, a goodovercharge-overdischarge property and a long life time, and they can beused repeatedly. A production of a lead storage battery with a largecapacity is expected. These characteristics for a lead storage batterylargely depend on the property of battery separators. The followingrequirements are desirable for lead storage battery separators; anaffinity to electrolytic solutions (an aqueous sulfuric acid solution ofabout 40 wt %), a large liquid-absorption rate, a high liquid-retentionproperty, resistances to alkalis and acids, durability in repeatedcharge/discharge processes, an electric insulation to prevent ashort-circuiting, a low electric resistance when they absorbelectrolytic solutions, a good permeability for passing gas and ionsreleased in batteries, a thin size suitable for small batteries, anuniform thickness, and a high tensile strength, etc.

At present, non-woven fabrics containing glass fiber is used for aseparator of a lead storage battery. Separators of a mixture of glassfiber and cellulose fiber bounded with a resin are also proposed(Japanese Laid-Open Patent Publication No. S59-73842 (1984)), and thefollowing separator is also proposed; a mixture of powder of inorganicmaterials and a glass fiber is further more mixed with an acid-resistantsynthetic fiber, and which are bound by a resin binder (JapaneseLaid-Open Patent Publication No. H8-130001 (1996), Japanese Laid-OpenPatent Publication No. H11-260335 (1999)). These separators are heavyand expensive. In addition, there is a problem that the resin used forthe binding is exfoliated. On the other hand, a lead-storage batteryseparator made of non-woven fabric of polyolefins gives a low-cost, alightweight, and a high mechanical strength. When a separator made ofsynthetic pulps (non-woven fabrics of polyolefins) impregnated with asurfactant (Japanese Laid-Open Patent Publication No. H5-86562) is used,the surfactant is released in use and the absorption property of anelectrolytic solution of the separator is decreased. An acid batteryseparator was prepared by an addition polymerization of a hydrophilicmonomer and polyethylene glycol diacrylate to a synthetic pulp ofpolyolefins (Japanese Laid-Open Patent Publication No. S62-268900(1987)). It was described that ammonium persulfate was used as aninitiator and any usual methods for polymerization could be employed.However, it is impossible to bind another polymer to polyolefins by theusual polymerization methods proposed in this patent. It is consideredthat the polymer resin obtained by the polymerization of a monomerseemed to be impregnated into the synthetic pulp of polyolefins and themixture made solidification. In this case, the long lifetime of theseparator can not be expected because the polyolefin fibers should beseparated from the polymer resin by the repeated charge/dischargeprocess in the battery.

Thus, the present invention has been carried out to prepare a leadstorage battery separator which gives no problems of separators used sofar, a lead storage battery separator which gives a high absorptionproperty of electrolytic solutions, resistances to alkalis and acids, alow-cost, a lightweight and a high mechanical strength, and theseproperties give an excellent durability because its hydrophilicity wasmade by a real chemical bonding.

(Non-Woven Fabrics for Battery Separator)

Non-woven fabrics for a battery separator prepared by the presentinvention are explained below. Webs for non-woven fabrics are notespecially limited. Polyolefin resins are used as main materials forwebs; non-woven fabrics prepared by various dry methods such as a spunbond, melt blow, spun lace, card, sintering, needle punch, cross layer,random weber, air-foaming and air-ray, or non-woven fabrics made by awet paper machine, or woven fabrics made with warps and wefts areapplicable. In addition, their laminates or bonded fabrics are alsoavailable.

A wet paper machine method has an advantage that fibers with variousdiameters or several kinds of fibers are mixed together at an arbitrarymixing ratio. Namely, fibers with various forms such as a staple formand a pulp form and fibers with various diameters from a fine fiberbelow 7 μm to a thick fiber are available in this method. This methodgives webs of very excellent characteristics as compared with the othermethods. On the other hand, as the spun bond method and the melt blowmethod give non-woven fabrics made of fine fibers, a separator made ofthese non-woven fabrics is favorable for preventing an electrical shortcircuit between a positive pole and a negative pole in a battery.Especially, to improve a fine structure of a separator, polyolefinfibers with a diameter of 0.1 μm to 15 μm are preferable, and thelaminate of a spun bond non-woven fabric and a melt brow fabric or theirbonded materials are preferable for the battery separator.

A unit weight and a thickness of a non-woven fabric suitable for analkali battery separator can be determined by considering the conditionssuch as a fiber diameter in a fabric, a retention property forelectrolytic solutions, and a fine structure (a property to prevent asmall electrical short circuit). As an alkali battery separator, a thinfabric gives a good wettability with electrolytic solutions and isfavorable for a miniaturization of a battery. However, when a separatoris too thin, it causes problems of a low mechanical strength and anelectrical short circuit. In addition, when a separator is too thick ortoo high in density, it takes a long time to immerse the separator in anelectrolytic solution and a problem in a charge and discharge process iscaused. Furthermore, when a diameter of fiber in a non-woven fabric isvery small, the following advantages are given; an increase in astrength for a needling, a prevention of a small electrical shortcircuit, an increase in an retention property of electrolytic solutions,and an improvement of a life cycle of a battery, but the followingdisadvantages are caused; a decrease in a permeability of oxygengenerated from a positive pole at a charge process, an increase in aninner pressure of a battery and a degradation of a property of a batteryat a rapid charge-discharge process.

As a separator of an alkali battery, a non-woven fabric with a pore sizeof 1-200 μm, a ratio of vacancy of 30-80 v/v %, a thickness of 20-500μm, a fiber diameter of 1-100 μm, and a unit weight of 5-100 g/m² arepreferably used. Considering these conditions, an alkali batteryseparator that has a large wettability with an electrolytic solution, ahigh retention property of an electrolytic solution and a highpermeability of oxygen can be obtained.

On the other hand, a lead storage battery needs an appropriatethickness, a high strength and a large liquid retention property. As aseparator of a lead storage battery, a non-woven fabric with a pore sizeof 1-200 μm, a ratio of vacancy of 30-80 v/v %, a thickness of 500-1200μm, a fiber diameter of 1-100 μm and a unit weight of 100-300 g/m² ispreferably used.

Batteries (or cells) suitable for the separators prepared by the presentinvention are as follows. Examples of primary batteries are analkali-manganese battery using an alkaline electrolytic solution, amercury cell, a silver oxide cell, an air cell, a silver chloride cell,a lithium battery, a manganese battery using an acid electrolyticsolution, etc.

Examples of secondary batteries are an alkaline storage battery using analkaline electrolytic solution (an Edison battery), a nickel-cadmiumbattery (a Jungner battery), a nickel-hydrogen battery, and a leadstorage battery using an acid electrolytic solution, etc. Separatorsprepared by the present invention can be used instead of paperseparators which have been so far used in batteries.

(2) Materials for Wiping/cleansing

At present, a disposable wiping/cleansing material prepared as followsmainly available on the market, that is, a conjugate fiber made withpolyester fiber, polyolefin fiber and other synthetic fiber is mixedwith rayon fiber which gives a hydrophilicity, and then, the mixedmaterial is impregnated with a surfactant. When the disposablecleansing/wiping material is made with a polymer material improved inthe water absorption property by the present invention, the materialgives a lightweight, a high mechanical strength, a high absorptionproperty of water and an aqueous surfactant solution and durability inuse. It can be used repeatedly several times by washing with water.

(3) Water-Absorption Material

A material with a water absorption property prepared by the presentinvention is represented.

(4) Water Retention Material

A hydrophilic polyolefin non-woven fabric improved by the presentinvention is useful for a water retention material which is availablefor supplying water to plants. To prepare a water retention material,the material of woven fabrics, non-woven fabrics, fibers, and cutdisposable fibers are available. The diameter of component fibers inthese materials is preferably from 10 μm to 500 μm for convenience.

(5) Medical/Sanitary/Cosmetic Supply

For example, diapers, sanitary supplies, bandages, gauze, sanitarynapkins, disinfecting patches/tapes, cosmetic supplies forcleaning/cleansing/face packing and padding, etc. are given. Inaddition, as the polymer materials improved by the present inventionhave a good affinity to a human body system, they are available for manykinds of medical accessories or supplies. For instance, vascular grafts,artificial joints, tube/thread/plate-like polymer materials, catheters,tubes or other items for draining, body fluid absorbing materials,contact lenses, lenses for goggles, bandages of synthetic fibers andinstillation accessories are given.

The inner part of disposable diapers or sanitary supplies containsmaterials having a water absorption property which are made of pulp,starch and polyacrylic acid, etc. and the outside part of them iscovered with a material having a water repellency which prevents thepassing of urine, water and blood, etc. and the surface of the innerpart is covered with polyolefin non-woven fabrics with a hydrophilicproperty. Water generated from a body is passed through the innerhydrophilic non-woven fabric and absorbed by the water absorptionmaterial. A hydrophilic polyolefin non-woven fabric is the mostpreferable material because it is strong and not easily broken in water.However, the method to give a hydrophilicity to the non-woven fabricsused in the inner material is only to dip them in surfactants orwater-soluble reagents, which is easily removed by rinsing in water. Inaddition, the effect of surfactants to skins is worrying. Thus, a cheap,easy and durable method to improve a hydrophilicity of a polymericmaterial is expected. Polyolefin materials improved in a waterabsorption/retention property which are prepared by the presentinvention are the most favorable for the fabrics used for the cover ofthe inside of disposable diapers and sanitary supplies. In addition,polymer materials with a high water absorption property which areprepared by the present invention are also available for waterabsorption materials used as an inner pad of disposable diapers orsanitary supplies. The improved materials by the present invention arelight in weight, mechanically strong and safety, and give a durabilityfor repeating uses. In addition, polymer materials obtained by thepresent invention give a hydrophilic property or a water absorptionproperty, and they are light and strong. As they can be impregnated withdetergents, chemicals and adhesives, they are available for gauze, fiberproducts for wiping, disinfecting cloth patches or tapes, and the othercosmetic supplies. When they are used for disposablemedical/sanitary/cosmetic supplies, each of a woven fabric or anon-woven fabric is preferably used as a material's form, and the unitweight and thickness of the material are appropriately selected. Adiameter of fibers in a non-woven fabric, 1-500 μm is easily used.

(6) Internal Materials for Clothing/bed/bedclothes

The polymer materials having a hydrophilicity and a water absorptionproperty obtained by the present invention are light in weight andmechanically strong. When their water absorption ability is controlledin a preferable extent, they are suitable for fiber products of clothesand an inner material for beds and bedclothes.

(7) Filter Mediums

Filter mediums of porous films made of polyolefins, polysulfone, andpolyester, etc. give a mechanical strength and a low hydrophilicity ascompared with paper filters. They are not available for the filtrationof aqueous solutions because of the low hydrophilicity. At present, theyare coated with surfactants or water-soluble polymers in order toimprove the hydrophilicity. However, the hydrophilic layer of thefilters is non-durable and is easily dissolved in filtrates in theprocess of filtration. When the hydrophilic treatment of the presentinvention is applied for the filter mediums, it is expected that filtermediums with a durable water absorption property are obtained.

(8) Materials for Microbial Culture Medium

As water retention materials obtained by the present invention give ahigh water absorption property, a large mechanical strength, and a largemicrobial fertility, they are suitable as the materials of a microbialculture medium. Various forms of materials such as woven fabrics,non-woven fabrics, fibers and cut disposable fibers are available. Adiameter of component fibers in these materials is preferably from 10μto 500 μm.

(9) Members of Writing Materials

Most of writing materials such as various ball-point pens withwater-soluble ink, felt-tip pens, brush pens and fountain pens containmembers made of plastics. At present, plastic materials made of ABSresin, polyester and nylon are treated by a plasma treatment or a coronadischarge treatment to improve the affinity to water-soluble ink andthey are mainly used as members for writing materials. Instead of thesematerials, polyolefins such as polypropylene and polyethylene areimproved and can be used for the members of writing materials, whichgive advantages of lightweight, safety, etc. The present invention makesit possible to improve the hydrophilicity of usual hydrophobic plasticmaterials and to use the improved materials for the plastic members ofwriting materials, which have a good absorption/retention property ofwater-soluble ink; for example, hydrophilic members such as ink-tanks,ink-collectors, heads of brush pens, ink-absorbing polyester fibers andpolyurethane sponges can be prepared.

(10) Orthodontic Brackets

The present invention can improve an adhesion property of polymermaterials. As this improvement is available for various materials whichneed a good adhesion property, such as composites and fibers used forfiber reinforced plastics, it is also available to improve the adhesionproperty of orthodontic brackets.

(11) Polymer Composites

The adhesion property of fibers mixed in polymer composites or in fiberreinforced plastics is improved and the fibers are applied for makingstrong polymer composites. The adhesion property of fibers mixed inpolymer composites or in fiber reinforced plastics are improved by thepresent invention and they are applied for making strong polymercomposites.

(12) Synthetic Papers

Synthetic papers made of polymer materials such as polyolefins(polyethylene and polypropylene, etc.) and polyester, etc. are whitenedby adding air bubbles or fillers, and they are used as alternativepapers. The present invention can improve a hydophilicity, an adhesionproperty and a printing property of synthetic papers.

(13) Materials with Improved Adhesion Property

In addition to the orthodontic brackets and the fibers used forcomposites, the property of the other materials such as various polymerfilms and molded materials is also improved. The adhesion propertybetween the same kind of materials or different materials can beimproved.

(14) Application of Hydrophilic Film

The present invention gives a high hydrophilicity to polymer films ofpolyolefins and polyester, etc. For instance, water-absorption polyesterfilms give a good adhesion property and a wettability with water, andthey show an anti-fogging property when they are put on glasses andmirrors.

BEST METHODS FOR CARRYING OUT THE INVENTION

The present invention is not limited to the embodiments described hereor by the examples which follow.

Used materials, reagents and test/evaluation methods are given below.

(A) Polymeric Materials

(1) Polypropylene non-woven fabric 1: Unit weight 40 g/m², thickness0.30 mm (measured by a thickness gauge, Model H of Ozaki Seisakusho Co.,Ltd., the other thicknesses are measured similarly) and a spunbondednon-woven fabric of fineness 2 d, with embossing finish. They were usedin Examples 1, 2, 3, 8 and 9.

(2) Polypropylene non-woven fabric 2: Unit weight 22 g/m², thickness0.18 mm, spunbonded non-woven fabric of fineness 2 d, with embossingfinish. It was used in Example 7.

(3) Polypropylene non-woven fabric 3: Made by a wet paper machinemethod. Unit weight 45 g/m², thickness 0.31 mm and fineness 2 d. Theywere used in Examples 4, 5 and 6 and Comparative Examples 1 and 2.

(4) Polyester non-woven fabric: Polyethylene terephthalate-made, unitweight 15 g/m², thickness 0.15 mm and fineness 2 d. It was used inExample 11.

(5) Polyethylene film: Unit weight 15 g/m² and thickness 0.05 mm. It wasused in Example 13.

(6) Polypropylene plain cloth: Numbers of warp 98/inch and weft 74/inch,filament fineness 3.3 d and thickness 0.12 mm. It was used in Example 12and Comparative Example 3.

(7) Polypropylene film: Unit weight 18 g/m² and thickness 0.05 mm. Theywere used in Examples 14, 15, 16, 17, 22 and Comparative Examples 5 and6.

(8) Polypropylene/polyethylene conjugated fiber-made non-woven fabric:Non-woven fabric made with a conjugated fiber of polypropylene andpolyethylene. Unit weight 20 g/m², thickness 0.12 mm and fineness 2 d.It was used in Example 10.

(9) Cotton plain cloth: Yarn size (warp and weft, 40/1) and thickness0.27 mm. It was used in Comparative Example 4.

(10) Polypropylene non-woven fabric 4: Produced by a wet paper machinemethod. Unit weight 151 g/m², thickness 1.00 mm and fineness 2 d. It wasused in Example 23.

(11) Polypropylene non-woven fabric 5: Produced by a spunbond method.Unit weight 50 g/m², thickness 150 μm, fineness 1 d and fiberlength=continuous filament. It was used in Example 29.

(12) Non-woven fabric of polyethylene/polyester conjugated sheath-coretype fiber: Non-woven fabric made of conjugated sheath-core type fiberwith a core of polyester and a sheath of polyethylene. Mixing ratio ofpolyester: 50 vol. %. Produced by thermal melting method. Unit weight 27g/m², thickness 30 μm, fineness 3 d and average fiber length=5.1 cm. Itwas used in Example 31.

(13) Polypropylene non-woven fabric 6: Non-woven fabric made by aspunbond method. Unit weight 20 g/m², thickness 0.21 mm and fineness 2d. Especially, this is prepared for a medical/sanitary use and issuitable for a non-woven fabric used for a disposable diaper, amedical/sanitary supply, a napkin and a cosmetic supply, etc. It wasused in Example 32.

(14) Porous polyethylene film: Used for a filter medium. Product ofsuper-high-molecular weight polyethylene (average molecular weight, over5 millions), unit weight 30 g/m², thickness 0.060 mm, and an averagediameter of voids is 1.0 μm. It was used in Example 24.

(15) Polypropylene synthetic paper: A film product which is white andcontains a lot of air bubbles, unit weight 92 g/m² and thickness 0.13mm. It was used in Example 25.

(16) Polyester film: A film of polyethylene terephthalate. Unit weight72 g/m² and thickness 0.06 mm. It was used in Example 30.

(17) Carbon fiber: Source material is polyacrylonitrile fiber.Continuous filaments with average diameter of 1.4 μm. It was used inExample 26.

(18) Wool woven fabric: Unit weight 188 g/m² and thickness 0.5 mm. Itwas used in Example 27.

(19) Members of writing materials: A polypropylene-made ink collector,outside diameter 6-8 mm, inside diameter 2-4 mm, weight 0.61 g andlength 28 mm. A polypropylene-made ink tank; outside diameter 10 mm,inside diameter 2-8 mm, weight 2.2 g and length 87 mm. They were used inExample 28.

(20) Battery separator made of glass fiber: Thickness 1.0 mm, unitweight 342 g/m², density 0.2 g/m³, fineness 10 μm, fiber length 4-8 cm,space volume ratio 93% and water absorption 780%. It was used inComparative Example 7.

(21) Orthodontic brackets: Size 2.23×3.0×3.8 mm, weight about 31 mg, apolypropylene molded material reinforced with aluminium fitment. It wasused in Example 33.

(B) Hydrophilic Polymer

(1) Polyvinyl alcohol (PVA): A product of Wako Junyaku Co., Ltd., codenumber 160-11485 (degree of polymerization=1500-1800); used in Examples1, 3, 4, 10, 11, 12, 13, 15, 17, 22, 23, 24, 25, 26, 27, 29, 30, 31, 32and Comparative Examples 1 and 6.

(2) Sodium carboxymethylcellulose (CMC): A product of Wako Junyaku Co.,Ltd., code number 039-01355; It was used in Examples 5, 6, 16, 28, 33and Comparative Example 2.

(3) Starch: Potato starch (a product of Wako Junyaku Co., Ltd., codenumber 191-03985); It was used in Example 7.

(4) Agar: Agar powder (a product of Wako Junyaku Co., Ltd., bacterialculture medium use, code number 010-08725); It was used in Example 8.

(5) Aqueous silk sericin solution: Cocoons of Bombyx mori were boiled inan aqueous solution of 5% sodium carbonate. Fibroin was removed from theobtained mixture, and the obtained liquor was neutralized with a diluteHCl solution and the obtained solution was dialyzed in distilled water.The solution was concentrated to about a half of the original volume byair-drying. Thus, a solution of sericin with about 0.9 wt % wasobtained. It was used in Example 2.

(6) Aqueous silk fibroin solution: Cocoons of Bombyx mori were washed ina boiling aqueous solution of 5% sodium carbonate. Fibroin removed fromthe obtained mixture was dissolved in a saturated aqueous solution ofcalcium chloride or lithium bromide by heating. The resulting solutionwas filtered and dialyzed in distilled water. The solution wasconcentrated to about ⅕ of the original volume by air-drying. Thus, asolution of fibroin with about 20 wt. % was obtained. It was used inExample 9.

(7) Gelatin: A product of Wako Junyaku Co., Ltd., code number 077-03155.It was used in Example 14.

(C) Reagents

(1) Cerium ammonium nitrate (IV) (CAN): It was used in Examples 1, 8, 9,16, 22, 23, 24, 25, 30 and 31.

(2) Potassium persulfate (KPS): It was used in Examples 2, 3, 6, 7, 10,11, 12, 13, 14, 15, 17, 22, 23, 24, 25, 26, 27, 28, 30, 31, 32, 33 andComparative Examples 1, 2, and 6.

(3) 2,2′-Azobisisobutylonitrile (AIBN): A product of Wako Junyaku Co.,Ltd., code number 019-04932. It was used in Examples 28 and 29.

(4) Methanol: A product of Wako Junyaku Co., Ltd., code number136-09475.

(5) Toluene: A product of Wako Junyaku Co., Ltd., code number 204-01866.

(D) Ozone Treatment

A specimen was put in a hard glass vessel of 2L volume (with an inletand an outlet for gas) which was connected to an ozone generator (aproduct of Nippon Ozone Co., Ltd., ON-1-2 type). Then, ozone wasgenerated by the ozone generator with an ozone yield of 1 g/hr andconcentration of 20 g/m³, and a mixture of ozone and oxygen wasintroduced into the reaction vessel with a flow rate of 800 ml/min for20-120 minutes. The concentration of ozone was checked by an iodinetitration. The extent of oxidation of a specimen is checked by theinfrared spectroscopy; the ratio of absorbance at 1710 cm⁻¹ to that at973 cm⁻¹ was used.

(E) Plasma Treatment

A specimen (fabrics, films, etc.) was placed on a position between twoelectrodes in a reaction bath of a plasma generator (Yamato PR 500).After the pressure of the reaction bath was decreased to 0.27 Pa, amixture of argon and oxygen (1:1 volume ratio) was introduced in thereaction bath until the pressure was increased to 5.6 Pa. A glowdischarge was carried out mainly for 30 seconds to 3 minutes at anoscillation frequency of 13.56 MHz with a power supply of 40 W to 100 W.After the discharge, the introduction of a mixture of argon and nitrogenwas stopped, the pressure was raised to a normal pressure and thetreated specimen was taken out. The effect of the treatment was judgedfrom a contact angle of water to films.

(F) Water-Absorption Test 1

A specimen was put in a beaker containing water, and it was stirred witha glass rod. Then, the specimen was taken out of the beaker and hungdown until water drops were not found (for about 3 minutes). Theincrease in weight of a specimen (an amount of absorbed water) wasestimated by the subtraction of a weight of the dried specimen from aweight of the water absorbed specimen. The percentage of a weight ofabsorbed water to the dried weight of the specimen gives “waterabsorption (%)”.

Water absorption (%)=(weight of absorbed water/weight of driedspecimen)×100

(G) Water-Absorption Test 2

A specimen was put in a beaker containing water, which had been set in abath of an ultrasonic cleaner (an output power, 10W) and oscillated for10 minutes. Then, the specimen was taken out of the beaker and hung downuntil water drops were not found (for about 3 minutes). Similarly to theabove Test 1, a percentage of a weight of absorbed water to a weight ofthe dried specimen gives “water absorption (%)”.

(H) Washing Fastness Test 1

A specimen was put in an aqueous solution of 0.1 wt % weak-alkalinesoap, sodium aliphatic acid (a commercial name, Powder Soap of Lion Co.,Ltd.) and the mixture was boiled for 5 minutes with stirring. Thiswashing process was repeated a given times and the water absorption (%)was estimated at each time.

(I) Washing Fastness Test 2

A specimen was put in an aqueous solution of 0.4 wt % neutral detergent(a commercial name, Acron of Lion Co., Ltd.) and the mixture was boiledfor 5 minutes with stirring at a liquor ratio of 1/250. This washingprocess was repeated several times and the water absorption (%) wasexamined at each time.

(J) Tensile Strength Test

Specimens were cut in rectangles (size, 15 mm×70 mm), and each part of 1cm width from the edge of a specimen are clamped by cramps of a tensiletester (a SFV-55-0-20M of Imada Seisakusyo Co., Ltd.) and it was drawnat a rate of 20 mm/min. Each specimen was drawn along both a lengthwisedirection and a cross direction of the original material. As a change ina strength along the lengthwise direction was seen in a similar range tothat along the cross direction in each of the Examples, only the valuesalong the lengthwise direction are given in Table 3 (where, the strengthof the original material is defined as 1.0).

(K) Adhesion Strength

Rectangular specimens of 30 mm (along a lengthwise direction)×5 mm (awidth) are cut from treated or untreated materials. An adhesion of 0.1 gis put on each part of 5 mm width from the edge of a specimen and thespecimen was attached to a plywood board (thickness 2 mm and size 20mm×10 mm). The specimen attached to the plywood board is clamped withpolyethylene films and a 500 g weight is put on the surface of the filmfor 12 hours. Each part of 1 cm width from the edge of the specimen isclamped by the cramps of the tensile tester (Imada Seisakusyo Co., Ltd.;SFV-55-0-20M) and it is drawn at a rate of 30 mm/min to see peelstrength of the bonded part. The adhesion strength of an untreatedpolypropylene film was measured similarly to that described above and itwas defined as 1.0 and the relative value of each adhesion strength wasestimated.

A polycyanoacrylate type adhesive (Aron-alpha, a product of Toa GoseiCo., Ltd.) and a polyvinyl acetate emulsion type adhesive (Wood-usebond, a product of Konishi Co., Ltd.) are employed.

(L) Retention of Electrolytic Solutions

A weight of a dried specimen (size 5 cm×5 cm) was defined as W1. Aspecimen was dipped into an aqueous potassium hydroxide solution (30 wt%) for 5 minutes. The specimen was taken out of the solution and is hungon for 3 minutes. The weight of the specimen W2 was measured when liquiddrops were not seen. The following equation gives the absorption (%) ofan alkali solution.

Electrolytic solution retention (%)=100×(W2−W1)/W1

(M) Alkali-Resistance at High Temperature

A weight of a dried specimen (size 5 cm×5 cm) was given as W 1. Aspecimen was dipped in an aqueous potassium hydroxide solution (30 wt %)for 96 hours at 60° C. The specimen was taken out of the solution andwas spread and hung on for 3 minutes. The weight of the specimen W2 wasmeasured when liquid drops are not seen. Then the specimen was washedwith water and dried in vacuum, and the weight was represented as W3.The following equations give an absorption (%) of an electrolyticsolution and a weight decrease (%).

Electrolytic solution absorption (%)=100×(W2−W1)/W1

Weight decrease (%)=100×(W1−W3)/W1

(N) Self Charge/discharge Test

An improved non-woven fabric was assembled in a scaled nickel-hydrogenbattery of a coin-size (nominal capacity: 500 mAH). Three batteries wereprepared in this way. When the property of the batteries seemed to bestable, they were charged to 120% by an electric source of 0.1 C(Coulomb). After four cycles of a charge-discharge process, an averagevalue of a residual capacity for each battery was estimated at 45° C.after two weeks. The values are given in Table 3.

(O) Measurement of Contact Angle of Water

A contact angle measuring apparatus (a product of CA-X of Kyowa KaimenKagaku Co., Ltd.) was employed. A water drop of about 1 mm diameter wasput on a surface of a specimen by an injector at 20 degree C, and theware drop was enlarged by a video camera and the contact angle wasestimated.

EXAMPLE 1

Hydrophilic Treatment of Polypropylene Non-woven Fabric by the Method ofthe Foregoing Aspect 1 of this Invention (with Polyvinyl Alcohol (PVA)

A polypropylene fabric 1 (0.3 g, size 50 mm×50 mm) was treated withozone for 20 minutes. An IR spectrum of the ozone-treated fabric wasobserved and the ratio of the absorbance at around 1710 cm⁻¹ to that ataround 973 cm⁻¹ was estimated as 0.08 by the base line method. Then, theozone-treated fabric was put in a vessel containing 100 ml of water, 1 gof PVA, 10 mg of cerium ammonium nitrate (IV) (CAN) and 15 ml ofmethanol. The reaction mixture was set in a water bath at 50° C. for 2hours. After the treatment, the fabric was washed with water and dried.Relation between values of water absorption (%) of the fabric and thenumber of washing fastness test is given in Table 1. The lowering of thehydrophilicity of the treated fabrics was very small.

EXAMPLE 2

Hydrophilic Treatment of Polypropylene Non-woven Fabric by the Method ofAspect 1 (with Silk Sericin)

A polypropylene fabric 1 (0.3 g) was treated with ozone for 30 minutes.Then, the ozone treated fabric was put in a vessel containing 100 ml ofwater, 10 mg of potassium persulfate, 3 ml of methanol and 5 ml of asilk sericin solution. The reaction mixture was maintained at 80° C. for2 hours with stirring. After the treatment, the fabric was washed withwater and examined by “Washing fastness test 2”. The weight-change ofthe specimen after the hydrophilic treatment was not observed in theorder of about 0.1 mg. As silk sericin was a protein, “Washing fastnesstest 2” using a neutral detergent was carried out. Relation betweenwater absorption (%) of the fabric and the number of washing fastnesstest was given in Table 1. A considerable change in the hydrophilicityby the laundry was not seen. As far as the treated fabric is washed witha neutral detergent, the practical hydrophilicity can be maintained.Water absorption (%) was tested by “Water-absorption test 2”.

EXAMPLE 3

Hydrophilic Treatment of Polypropylene Non-woven Fabric by the Method ofAspect 1 (with PVA)

A polypropylene fabric 1 (0.3 g) was treated with ozone for 30 minutes.Then, the ozone treated fabric was put in a vessel containing 100 ml ofwater, 30 mg of potassium persulfate, 0.3 g of PVA and 3 ml of methanol.The reaction mixture was maintained at 80° C. for 2 hours with stirring.After the treatment, the fabric was washed with water and examined by“Washing fastness test 1”. The water absorption property on the fabricsexamined by “Water-absorption test 1” were from 800% to 1100%. Theweight-change of the specimen after the hydrophilic treatment was notobserved in the order of about 0.1 mg. The results were given inTable 1. Even after six times of the washing fastness test 1, the waterabsorption property of the treated fabric was kept over 810%.

EXAMPLE 4

Hydrophilic Treatment of Polypropylene Non-woven Fabric by the Method ofAspect 1 (with PVA)

A polypropylene non-woven fabric 3 (0.3 g) treated with ozone for 30minutes was put in a vessel containing 100 ml of water, 0.3 g of PVA and3 ml of methanol. The reaction mixture was maintained at 80° C. for 2hours with stirring. After the treatment, the fabric was washed withwater and examined by “Water-absorption test 1”. The water absorptionproperty on the fabrics examined by three times of “Water-absorptiontest 1” was 650%. The results are given in Table 1. Even after six timesof the washing fastness test 1, the water absorption property of thetreated fabric was kept over 650%.

Comparative Example 1

Hydrophilic Treatment of Polypropylene Non-woven Fabric Using PotassiumPersulfate and PVA

A polypropylene fabric 3 (0.3 g) with no ozone-treatment was put in avessel containing 100 ml of water, 30 mg of potassium persulfate, 0.3 gof PVA and 3 ml of methanol. The reaction mixture was maintained at 80°C. for 2 hours with stirring. After the treatment, the fabric was washedwith water and “Washing fastness test 1” was carried out. The waterabsorption of the treated fabric by “Absorption test 1” gave 760%. Thewater absorption decreased to 260% after six times of the washingfastness test. The results are given in Table 1. The weight of thespecimen after the hydrophilic treatment was 4 weight % of the originalweight. Thus, when the activation step was not carried out, the waterabsorption property of the treated specimen was markedly decreased.

EXAMPLE 5

Hydrophilic Treatment of Polypropylene Non-woven Fabric by the Method ofAspect 1 (with CMC in the Absence of Initiators)

A polypropylene fabric 3 (0.3 g) was ozone-treated for 30 minutes andwas put in a vessel containing 100 ml of water, 0.3 g of CMC and 3 ml ofmethanol. The reaction mixture was maintained at 80° C. for 2 hours withstirring. After the treatment, the fabric was washed with water. Afterthree times of “Washing fastness test 1”, the water absorption of thetreated fabric was 580%. The results are given in Table 1.

EXAMPLE 6

Hydrophilic Treatment of Polypropylene Non-woven Fabrics by the Methodof Aspect 1 (with CMC)

A polypropylene fabric 3 (1.0 g) ozone-treated for 30 minutes was put ina vessel containing 200 ml of water, 0.5 g of CMC, 3 ml of methanol and50 mg of potassium persulfate. The reaction mixture was maintained at80° C. for 1 hour with stirring. After the treatment, the fabric waswashed with water and “Washing fastness test 1” was carried out. Afterthree times of the washing fastness test, the water absorption was 773%.The results are given in Table 1.

Comparative Example 2

Hydrophilic Treatment of Polypropylene Fabric without the ActivationTreatment

A polypropylene fabric 3 (1.0 g) with no activation treatment was put ina vessel containing 200 ml of water, 0.5 g of CMC, 50 mg of potassiumpersulfate and 3 ml of methanol. The reaction mixture was maintained at75° C. for one hour with stirring. After the treatment, the fabric waswashed with water and “Washing fastness test 1” was carried out. Thewater absorption was 630% after the first washing fastness test. Theresults are given in Table 1. After three times of the washing fastnesstest 1, the water absorption is decreased to 250%.

EXAMPLE 7

Hydrophilic Treatment of Polypropylene Non-woven Fabric by the Method ofAspect 1 (with Starch)

A polypropylene non-woven fabric 2 (1.0 g) treated with ozone for 30minutes was put in a vessel, and 100 ml of water and 1.0 g of potatostarch were put in the vessel. After the starch was dissolved byheating, 50 mg of potassium persulfate and 3 ml of methanol were addedin the reaction mixture. The reaction mixture was maintained at 60° C.for 1 hour with stirring. Then, the fabric was washed with water and“washing fastness test 1” was carried out. The water absorption of thetreated fabric estimated by “Water absorption test 1” was 600%. Afterthree times of the washing fastness test 1, the water absorption of thetreated fabric was 530%. The results are given in Table 1.

EXAMPLE 8

Hydrophilic Treatment of Polypropylene Non-woven Fabric by the Method ofAspect 1 (with Agar Powder)

A polypropylene non-woven fabric 1 (1.0 g) was plasma-treated for 30seconds at a power supply of 60V and it was put in a vessel. A 100 ml ofwater and 1.0 g of agar powder were put in the vessel, and they weredissolved by heating. Then, 60 mg of cerium ammonium nitrate (IV) and 3ml of methanol were added in the mixture. The reaction mixture wasmaintained at 60° C. for 1 hour with stirring. After the treatment, thefabric was washed with water. The water absorption of the treated fabricestimated by “Water absorption test 1” was 595%. After two times of“Washing fastness test 1”, the water absorption of the treated fabricwas 410%. The results are given in Table 1.

EXAMPLE 9

Hydrophilic Treatment of Polypropylene Non-woven Fabric by the Method ofAspect 1 (with Silk Fibroin)

A polypropylene non-woven fabric 1 (0.5 g) treated with ozone for 30minutes was put in a vessel. Then, 100 ml of water, 60 mg of ceriumammonium nitrate (IV), 3 ml of methanol and 3 ml of a silk fibroinsolution (concentration: 20 wt %) were added in the vessel. The reactionmixture was maintained at 60° C. for 2 hours with stirring. After thetreatment, the fabric was washed with water. After two times of “Washingfastness test 2” with a neutral detergent, the water absorption of thespecimen was 510%. The results are given in Table 1. The change in theweight of specimen after the hydrophilic treatment was not observed inthe range of about 0.1 mg.

EXAMPLE 10

Hydrophilic Treatment of a Polypropylene-polyethylene ConjugatedFiber-made Non-woven Fabric by the Method of Aspect 1 (with PVA)

A non-woven fabric of polypropylene-polyethylene conjugated fiber (1.0g) was ozone-treated for 30 minutes. Then, the fabric was put in avessel, and 100 ml of water, 1.0 g of PVA, 60 mg of potassium persulfateand 3 ml of methanol were added in the vessel. The reaction mixture wasmaintained at 60° C. for 2 hours with stirring. After the treatment, thefabric was washed with water and “Washing fastness test 1” was carriedout. The water absorption of the treated fabric estimated by “Waterabsorption test 1” was 1000%. The weight change of a specimen after thehydrophilic treatment was not observed in the range of about 0.1 mg.After five times of the washing fastness test 1, the water absorption ofthe treated fabric was 850%. The results are given in Table 1.

EXAMPLE 11

Hydrophilic Treatment of Polyethylene Terephthalate Non-woven Fabric bythe Method of Aspect 1 (with PVA)

A polyethylene terephthalate non-woven fabric (0.8 g) was ozone-treatedfor 30 minutes. Then, the fabric was put in a vessel, and 40 mg ofpotassium persulfate, 100 ml of water, 0.5 g of PVA and 5 ml of methanolwere added in it. The reaction vessel was changed to be under nitrogenatmosphere. The reaction mixture was maintained at 70° C. for 2 hourswith stirring. After the treatment, the fabric was washed with water.The water absorption of the treated fabric estimated by “Waterabsorption test 1” was 1200%. After five times of the washing fastnesstest 1, the water absorption of the treated fabric was 860%. Theincrease in the weight of specimen after the hydrophilic treatment was0.5%. The results are given in Table 1.

TABLE 1 Water absorption (%) of treated non-woven fabrics after washingfastness test Number of washing fastness test Examples 1 2 3 4 5 6Example 1 1060 950 820 800 780 780 Example 2 650 620 615 610 Example 31080 930 830 820 810 810 Example 4 820 730 650 650 Example 5 679 640 580Example 6 790 773 773 Example 7 600 530 Example 8 595 410 Example 9 640510 Example 10 1000 850 Example 11 1200 860 Comparative Example 1 760460 330 320 300 260 Comparative Example 2 630 350 250 Unit: %:

EXAMPLE 12

Hydrophilic Treatment of Polypropylene Plain Cloth by the Method ofAspect 1 (with PVA)

A polypropylene plain cloth (1.88 g) was ozone-treated for 30 minutes,and the treated cloth was put in a vessel. Then, 200 ml of water, 1.61 gof PVA, 60 mg of potassium persulfate and 10 ml of methanol were addedin it. The reaction mixture was maintained at 80° C. for 2 hours withstirring. After the treatment, the cloth was washed with water anddried. The water absorption of the treated fabric estimated by “Waterabsorption test 1” was 93.0%. After two times of “Washing fastness test1”, the water absorption of the treated fabric was 81.2%.

Comparative Example 3

A water absorption of an untreated polypropylene plain cloth examined by“Water absorption test 1” was 30%.

Comparative Example 4

A water absorption of a cotton plain cloth examined by “Water absorptiontest 1” was 108%.

EXAMPLE 13

Hydrophilic Treatment of Polyethylene Film by the Method of Aspect 1(with PVA)

A polyethylene film (0.5 g) washed well with methanol was ozone-treatedfor 60 minutes. The film was put in a vessel, and 100 ml of water, 40 mgof potassium persulfate, 0.2 g of PVA and 3 ml of methanol were added init. The reaction mixture was maintained at 70° C. for 2 hours withstirring. After the treatment, the film was washed with water and“Washing fastness test 1” was carried out. The water absorption of thetreated film estimated by “Water absorption test 1” was 80%. The weightincrease of the specimen after the hydrophilic treatment was 0.2%.

EXAMPLE 14

Hydrophilic Treatment of Polypropylene Film by the Method of Aspect 1(with gelatin)

A polyethylene film (0.3 g) washed well with methanol was ozone-treatedfor 90 minutes. The film was put in a vessel, and 100 ml of water, 3 mlof methanol, 40 mg of potassium persulfate and 0.2 g of gelatin wereadded in it. The reaction mixture was maintained at 80° C. for 2 hourswith stirring. After the treatment, the film was washed with water and“Washing fastness test 1” was carried out. The water absorption of thetreated film examined by “Water absorption test 1” was 85%. The weightincrease of the specimen after the hydrophilic treatment was 0.3%.

EXAMPLE 15

Hydrophilic Treatment of Polypropylene Film by the Method of Aspect 1(with PVA)

A polyethylene film (0.3 g) washed well with methanol was plasma-treatedfor 60 seconds at a power supply 60V. The treated film was put in avessel and 100 ml of water, 3 ml of methanol, 40 mg of potassiumpersulfate and 0.2 g of PVA were added in it. The reaction mixture wasmaintained at 80° C. for 2 hours with stirring. After the treatment, thefilm was washed with water and “Washing fastness test 1” was carriedout. The water absorption of the treated film examined by “Waterabsorption test 1” was 75%. The weight increase of the specimen afterthe hydrophilic treatment was 0.2%.

EXAMPLE 16

Hydrophilic Treatment of Polypropylene Film by the Method of Aspect 1(with CMC)

A polypropylene film (0.3 g) washed well with methanol. Then, it wasozone-treated for 90 minutes. Then the treated film was put in a vessel,and 100 ml of water, 3 ml of methanol, 40 mg of CAN and 0.2 g of CMCwere added in it. The reaction mixture was maintained at 80° C. for 2hours with stirring. After the treatment, the film was washed with waterand “Washing fastness test 1” was carried out. The water absorption ofthe treated film (examined by “Water absorption test 1) was 57%. Theweight increase of the specimen after the hydrophilic treatment was0.2%.

Adhesion Test

Water absorption (%) examined by “Water absorption test 1” and, relativeadhesion strength for the specimens obtained in Examples 14, 15, 16 anduntreated films are summarized in Table 2. The values of adhesionstrength were given as relative values when each of the adhesionstrength for untreated film with polycyano acrylate adhesion orpolyvinyl acetate-system adhesive is defined as 1.0. It was seen thatthe adhesion strength of the treated film was increased by the presenthydrophilic treatment.

In addition, a contact angle of water to an untreated polypropylene was116° (this is applied similarly as below), and that of the specimen ofExample 15 was 49.7°; the improvement of hydrophilicity was ascertained.

TABLE 2 Relative adhesion strength Water absorption Polycyano PolyvinylExamples (%) acrylate acetate system Example 14 85 1.75 1.52 Example 1575 2.40 1.85 Example 16 57 1.68 1.55 Untreated 14 1.00 1.00 specimen

Comparative Example 5

Ozone-treatment of Polypropylene Films

A polypropylene film (0.3 g) was washed well with methanol, and then itwas ozone-treated for 30 minutes. The water absorption of the treatedfilm estimated by “Water absorption test 1” was 12% (that of untreatedfilm was 2.5%; this is applied similarly as below). The contact angle ofwater was 99.3°. The weight increase of the specimen after the treatmentwas 0.1%.

EXAMPLE 17

Hydrophilic Treatment of Polypropylene Film by the Method of Aspect 3

Polypropylene film (0.4 g) was washed well with methanol, and it wasimmersed in toluene for 1 minutes at 50° C. (liquor ratio 1:10). Then,it was ozone-treated for 30 minutes. The ozone-treated film was put in avessel, and 100 ml of water, 40 mg of potassium persulfate, 0.2 g of PVAand 3 ml of methanol were added in it. The reaction mixture wasmaintained at 80° C. for 2 hours with stirring. After the treatment, thefilm was washed with water and “Washing fastness test 1” was carriedout. A water absorption of the treated film estimated by “Waterabsorption test 1” was 52%. A contact angle of water was 83°. A weightincrease of the specimen after the treatment was 0.2%.

Comparative Example 6

Treatment of Polypropylene Film without an Activation Treatment

Polypropylene film (0.4 g) was washed well with methanol, and it wasimmersed in toluene for 1 minute at 50° C. (liquor ratio 1:10). Then, itwas put in a vessel, and 100 ml of water, 20 mg of potassium persulfate,0.2 g of PVA and 3 ml of methanol were added in it. The reaction mixturewas maintained at 80° C. for 2 hours with stirring. The water absorptionof the treated film estimated by “Water absorption test 1” was 17%. Acontact angle of water was 86°. A weight increase of the specimen afterthe treatment was 0.2%.

Thus, as described in Example 17, the polypropylene film obtained by thepresent invention gives a more higher hydrophilicity as compared withthat obtained without the ozone treatment.

EXAMPLE 18

Alkali Battery Separators

When a polymeric material with an improved hydrophilicity is used foralkali battery separators, it should have excellent properties in aretention of an electrolytic solution, a durability to alkalis and acharge/discharge property. The values in Examples 1, 3, 4 and 6 andComparative example 1 are given in Table 3.

TABLE 3 Water absorption Relative tensile Retention of Capacity (%)after 6 strength electrolytic Alkali-resistance after times' washing(Before solution (Decrease in self-discharge Examples fastness teststreatment = 1) (%) weight (%)) (%) Example 1 780 0.87 750 0.1 85 Example3 810 0.85 760 0.1 85 Example 4 680 0.92 480 0.2 82 Example 6 750 0.79540 0.0 90 Comparative 260 0.91 260 3.0 65 Example 1

As shown in Table 3, polypropylene non-woven fabrics (Examples 1, 3 and6) which were treated by the ozone-treatment and the polymer treatmentwith PVA or CMC in the presence of an initiator (cerium ammonium nitrate(IV) or persulfates) gave the durability in an alkali-resistanceproperty and a water absorption property. They are suitable for alkalibattery separators. A polyolefin non-woven fabric prepared by the ozonetreatment and the treatment with PVA in the absence of an initiator(Example 4) is also suitable for alkali battery separators as they givean excellent alkali-resistance property and a durable hydrophilicity. Onthe other hand, a polyolefin non-woven fabric prepared by the treatmentwith PVA and an initiator without the ozone treatment (Comparativeexample 1) gave a decrease in a water absorption property after thewashing fastness tests, a low retention property of an electrolyticsolution and a decrease in a battery content after a self-dischargeprocess as compared with Examples 1, 3, 4 and 6.

EXAMPLE 19

Application as a Microbial Culture Medium

Each of improved non-woven fabrics treated similarly to Examples 1 to 8was cut in two pieces of a size of 2 cm×2 cm, and they were aligned in apetri dish of diameter 8 cm and depth 2 cm without an overlapping.

A bouillon/agar solution 100 ml was prepared by dissolving meat extract(1 wt %), polypeptone (1 wt %), sodium chloride (0.5 wt %) and agar (0.5wt %) in water. The agar in the mixture was dissolved by using amicrowave oven, and a bouillon/agar solution 50 ml was infiltratedthrough said non-woven fabrics prepared by the present invention. Then,the mixture was cooled down to the room temperature. The non-wovenfabrics containing the bouillon/agar solution were put in the testtubes, which had been autoclaved for 15 minutes at 120° C. These testtubes were allowed to stand at 37° C. overnight. The following day,after confirming the asepsis, microbes (Escherichia coli K-12 strain,Salmonella Typhimurium LT-2 strain and Bacillus subtilis Marburg strain,etc.) were planted on the fabrics, and they were cultivated overnight at30 to 37° C. A microscopic observation showed that each of the microbeswas growing well.

EXAMPLE 20

Materials for Cleansing/wiping

Improved non-woven fabrics obtained by the Aspect 1 similarly toExamples 10 and 11 were cut into a fabric of 30 cm×30 cm size. Afterbeing absorbed by water, the fabric were used to clean a wooden table of1.2 m×1.2 m size for 1 minute, and the fabric was rinsed with water anddried. When this manner was repeated 10 times, the water absorptionproperty of the fabric was observed; a considerable decrease in thewater absorption property was not seen and the tensile strength gave adecrease of 20% of the original value.

EXAMPLE 21

Water Retention Materials for Plants

A non-woven fabric prepared similarly to Example 3 was put in a plantpot containing mud and water. The water absorption amount was 1200 g perfabric of 100 g. When this plant pot containing the non-woven fabricabsorbed water was covered with a polyethylene film, it did not need awater supply for a week.

EXAMPLE 22

Polypropylene Film Treated by the Method of Aspect 2

Polypropylene film (0.4 g) was washed well with methanol, and dried. Thefilm was then treated with ozone for 90 minutes. Then, the treated filmwas put in a vessel, and 3 ml of methanol, 100 ml of water, 20 mg ofpotassium persulfate and 0.2 g of PVA were added in it. The reactionmixture was maintained at 80° C. for 2 hours with stirring. After thetreatment, the specimen was washed with water for 5 minutes at 60° C.Then, the treated film was put in a vessel, and 10 mg of cerium ammoniumnitrate (IV) and 0.2 ml of acrylic acid were added in it. The reactionmixture was maintained at 80° C. for 2 hours with stirring. The waterabsorption of the treated film examined by “Water absorption test 1” was17%. A contact angle of water was 86°. A weight increase of the specimenby the treatment was 0.2%.

EXAMPLE 23

Polypropylene Non-woven Fabric Treated by the Method of Aspect 2, andIts Use for Lead Storage Battery Separators

A polyethylene non-woven fabric 4 (63.9 g, size 77 mm (width)×5.5 mm(length)×1 mm (thickness)) was ozone-treated for 45 minutes.

Then, the treated fabric was put in a cylindrical reaction vessel, and40 ml of methanol, 500 ml of water, 10 g of PVA and 400 mg of potassiumpersulfate were added in it. The reaction mixture was maintained at 80°C. for 2 hours with stirring. After this step, the specimen was washedwith boiling water for three minutes. Then, the obtained specimen wasput in a cylindrical reaction vessel, and 500 ml of water, 400 mg ofcerium ammonium nitrate (IV) and 20 ml of acrylic acid were added in it.The reaction mixture was maintained at 80° C. for 2 hours with stirring.The treated non-woven fabric was washed with an aqueous soup solution(conc. 0.1 wt %, liquor ratio=1/20) at 60° C., and rinsed well in waterand dried. The grafting was 2%. Its retention property of anelectrolytic solution (40 wt % sulfuric acid solution) was 650%. Whenthe relative tensile strength of an untreated fabric was defined as 1.0,the relative tensile strength of the treated fabric was 0.94.

Alkali-resistance test: The obtained specimen was dipped in an aqueouspotassium hydroxide solution (40 wt %) at 70° C. for a week. Then, thespecimen was sufficiently washed with water and dried. Its retentionproperty of an electrolytic solution (40 wt % of sodium hydroxide) was650%, and the relative tensile strength was 0.94.

Sulfuric acid-resistance test: The obtained specimen was dipped in anaqueous sulfuric acid solution (40 wt %) at 70° C. for a week. Thespecimen was sufficiently washed with water and dried. The retentionproperty of the specimen to the electrolytic solution (a retention % ofthe sulfuric acid solution) was 660%, and the relative tensile strengthwas 0.94.

Oxidant-resistance test: The obtained specimen was dipped in an aqueoushydrogen peroxide solution (concentration, 20 weight %) for one week at30° C. The specimen was sufficiently washed with water and dried. Theretention property of the obtained specimen to the electrolytic solution(a retention % of the sulfuric acid solution) was 600%, and the relativetensile strength was 0.94.

Electric property test: Hydrophilic polypropylene non-woven fabricsprepared by the present invention or glass fiber separators (Comparativeexample 7) which are extensively used for the separators in sealed-typelead storage batteries were assembled in sealed-type lead storagebatteries. The batteries gave a voltage 4 V and a capacity 3.8 Ah. Adischarge test was carried out and the time when the final voltage gave2.8 V at a discharge current of 13 A was observed. The results of theelectric property after a charge-discharge test are given in Table 4.

From these results, it is found out that a separator for a lead storagebattery using an excellent retention property of an electrolyticsolution, a long-life and a light weight can be produced inexpensively.

Comparative Example 7

Glass Fiber Separators

For comparison of battery properties, a glass fiber separator which wasextensively used for a separator in a sealed-type lead storage batterywas examined. The glass fiber separator is known to contain surfactantsfor water absorption. The retention property of an electrolytic solutionwas 560%. The results for the batteries using each of separators aregiven in Table 4.

TABLE 4 Items Example 23 Comparative example 7 Materials HydrophilicGlass fiber with polypropylene acid resistance non-woven fabric Electricresistance 0.0003 0.0040 (ohm dm³/one piece) Discharge time 750 700after 30 times of charge/discharge (sec) Discharge time 640 500 after100 times of charge/discharge (sec) Voltage after 4.0 3.7 selfdischarging (V) Initial water absorption 5.0 4.0 rate (cm/min) Waterabsorption rate 5.0 3.5 after 6 months (cm/min) Initial retentionproperty 650 560 of electrolytic solution (%) Retention property of 650480 electrolytic solution after 6 months (%)

These results suggest that the lead storage battery using a hydrophilicpolyolefin non-woven fabric prepared by the present invention gives anexcellent retention property of an electrolytic solution, a longlifetime and a lightweight. They can be produced with a cheaper price ascompared with the batteries prepared by the usual techniques.

EXAMPLE 24

Hydrophilic Treatment of Porous Polyethylene Film by the Method ofAspect 4 and Its Application

A porous polyethylene film of A4 size was washed with methanol anddried. Then, it was immersed in 100 ml of toluene at 50° C. for 5minutes. After wiping the toluene on the film, it was ozone-treated for60 minutes. The ozone-treated film was put in a vessel, and 400 ml ofwater, 100 mg of potassium persulfate, 5 g of PVA and 3 ml of methanolwere added in it. The reaction mixture was maintained at 80° C. for 2hours with stirring. After the treatment, the film was washed with anaqueous soap solution at 60° C. three times (500 ml water for eachwashing).

Then, the treated film was put in a vessel, and 400 ml of water, 100 mgof cerium ammonium nitrate (IV) and 5 ml of acrylic acid were added init. The reaction mixture was maintained at 80° C. for 2 hours withstirring under nitrogen atmosphere. The treated film was washed with anaqueous soap solution at 60° C. and washed well with water. The waterabsorption of the treated film estimated by “Water absorption test 1”was 200% (an untreated porous polyethylene film gave 5%). A contactangle of water could not measured because water was absorbed by thetreated film (a untreated porous polyethylene film gives 120°). A weightincrease of the specimen after the treatment was 2%. This hydrophilicporous polyethylene film gives excellent properties in analkali-resistance and an acid-resistance, and it is available for afiltration of water.

EXAMPLE 25

Hydrophilic Treatment of Polypropylene Synthetic Paper by the Method ofAspect 4

Polypropylene synthetic papers were treated by the method similar toExample 24 and the hydrophilic property was improved. The treatedsynthetic papers are possible to be written with water-soluble ink andthey could be bonded to papers with water-soluble glues (starch, CMC andPVA, etc.).

EXAMPLE 26

Hydrophilic Treatment of Carbon Fibers by the Method of Aspect 4 and ItsApplication for Composites

Carbon fiber 6.0 g was washed with methanol, dried and ozone-treated for30 minutes. Then, it was put in a vessel containing 100 ml of an aqueousPVA solution (containing 2 g of PVA) and 100 mg of potassium persulfatewas added in it.

The reaction mixture was maintained at 80° C. for 2 hours with stirring.After the treatment, the fiber was washed with an aqueous soap solution(concentration 0.1 wt % and liquor ratio 1/1000). After drying, thewater absorption increased to be 200% (untreated fiber gave 120%). Whenthe treated fiber was put on a surface of water, it sank in 3 seconds.But an untreated fiber did not sink in water even after one hour. Thetreated carbon fiber was mixed with an epoxy resin adhesive and themixture was dried. As a result, a rod of 5 mm×5 mm×100 mm size made of acomposite of epoxy resin and hydrophilically-treated carbon fiber wasobtained. As a comparison, a rod with the same size as the abovespecimen was prepared with epoxy resin and untreated carbon fiber. Thetensile strength of the rod containing hydrophilically-treated carbonfiber was five times of that of a rod containing untreated carbon fiber.

EXAMPLE 27

Hydrophilic Treatment of Wool Fiber by the Method of Aspect 1

Wool fiber (6.0 g) was washed with methanol, dried and ozone-treated for60 minutes. Then, it was put in 15 ml of an aqueous PVA solution(containing 0.375 g of PVA) in a vessel and 50 mg of potassiumpersulfate was added in it. The reaction mixture was maintained at 80°C. for 2 hour with stirring. After the treatment, the fiber was washedtwice with an aqueous solution of a neutral detergent (concentration 0.1wt % and liquor ratio 1/1000). After drying, the water absorptionincreased to be 380%. An untreated fiber gave 99%.

When water drops were put on an untreated wool fiber cloth and the clothwas inclined, they fell down. On the other hand, water drops were put onthe surface of the improved hydrophilic wool cloth, they were absorbedin 30 sec.

EXAMPLE 28

Hydrophilic Treatment of Writing Material Members Made of Polypropyleneof Aspect 4

The solvent treatment of five ink collectors and five ink tanks whichare made of polypropylene was carried out; they were dipped in tolueneat 40° C. for 5 minutes. Then, they were ozone-treated for 1 hour. Then,the treated specimens were put in a mixture of 50 mg of potassiumpersulfate, 200 ml of water and 0.1 g of CMC at 80° C. for 2 hours.Then, the specimens, 60 ml of water, 0.7 ml of acrylic acid and 50 mg ofAIBN were put in a Pyrex glass vessel, which was covered. The UV lightof a high pressure mercury lamp (Toshiba H400P lamp) was irradiated tothe reaction vessel at 30° C. for 2 hours; the distance between thevessel and the UV light was 20 cm. The ink collectors and tanks weretaken out of the reaction mixture and washed with a soap solution for 10minutes at 60° C. (concentration=0.1 wt % and a liquor ratio=1/500),washed with water and dried. The hydrophilic materials were obtained.The hydrophilic materials were soaked well when they were dipped inwater. A water-soluble ink was put into the treated ink tank, the inkinvolved in the tank did not easily pour out of it. On the other hand,untreated ink collectors and ink tanks did not absorb water. Whenwater-soluble ink was put in them, it did not wet their surface.

EXAMPLE 29

Hydrophilic Treatment of Polypropylene Non-woven Fabric by the Method ofAspect 4

A polypropylene non-woven fabric 5 (0.5 g) was washed with methanol anddried. Then, it was dipped in 100 ml of toluene for 5 minutes at 50° C.After wiping toluene on the surface of the fabric, it was treated withozone for 45 minutes. The treated fabric was put in a vessel and 100 mlof water, 10 mg of AIBN, 0.5 g of PVA and 5 ml of methanol were added init. The reaction mixture was maintained at 80° C. for 1 hour. After thetreatment, the fabric was washed with a soap solution at 60° C.(concentration 0.1 wt % and a liquor ratio 1/1000).

Then, the treated fabric was put in a Pyrex-glass vessel which containeda solution made of 30 ml of methanol, 10 mg of AIBN, 30 ml of water and0.3 ml of acrylic acid. The UV light of a high pressure mercury lamp(Toshiba H400P lamp) was irradiated to the reaction vessel at 30° C. for90 minutes; the distance between the vessel and the UV light was 20 cm.The treated fabric was washed with a soap solution at 60° C. for 10minutes, washed with water and dried. The water absorption property ofthe obtained material and the water absorption rate, were 200% and 5.2cm/min., respectively (an untreated fabric: 20% and 0 cm/min.). Thus, asthe obtained material gave durability in the water absorption propertyand excellent properties in alkali-resistance, acid-resistance and ananti-oxidation, it was suitable for a battery separator.

EXAMPLE 30

Hydrophilic Treatment of Polyester Film by the Method of Aspect 4

Polyester film (10 g) was dipped in 100 ml of toluene at 50° C. for 10minutes. When the surface of the film seemed to be dried apparently, theweight increase of the film was about 2%. Then, it was treated withozone for 30 minutes. The ozone-treated film was put in an Erlenmeyerflask, and 5 ml of methanol, 100 ml of water, 0.5 g of PVA and 0.1 g ofpotassium persulfate were put in the flask. The reaction mixture wasmaintained at 80° C. for 2 hours with stirring. After the treatment, thefilm was washed well with water at 60° C. Then, the film was put in areaction vessel, and 5 ml of methanol, 400 ml of water, 100 mg of ceriumammonium nitrate (IV) and 5 ml of acrylic acid were put in it. Thevessel was set under nitrogen atmosphere and maintained at 80° C. for 2hours. Then, the treated film was washed with a soup solution threetimes at 60° C. (concentration=0.1 wt % and a liquor ratio=1/100). Afterdrying, the treated film gave a contact angle of water, 22° (a untreatedfilm gave 71°). The improved film gave durability in a hydrophilicproperty, and was soaked almost completely with water. When the improvedfilm was stuck to a glass mirror with an adhesive, the miller gave ananti-fog property. The improved film could be bonded to variousmaterials with usual adhesives.

EXAMPLE 31

Hydrophilic Treatment of Non-woven Fabric of Polyethylene/polyesterConjugated Sheath-core Type Fiber by the Method of Aspect 4 and ItsApplication for Cleaning Wiper

A non-woven fabric of polyethylene/polyester sheath-core type conjugatedfiber (2.4 g) was immersed in 100 ml of toluene for 2 minutes at roomtemperature. Then, the fabric was taken out of toluene and it wassqueezed by a centrifugal separator (a rotation number, 1000 rpm) untilthe extent that the surface looked dry apparently. The weight increaseby this solvent treatment was about 4%. Then, it was treated with ozonefor 30 minutes. Then, the ozone-treated non-woven fabric was put in anErlenmeyer flask, and 5 ml of methanol, 100 ml of water, 0.5 g of PVAand 0.1 g of potassium persulfate were put in the flask. The flask wasset at 80° C. for 2 hours under nitrogen atmosphere. After thetreatment, the fabric was washed well with water. The obtained fabricwas squeezed (to the extent of water absorption, 300%).

Then, the obtained fabric was put in a vessel, and 40 ml of water, 100mg of cerium ammonium nitrate (IV) and 5 ml of acrylic acid were addedin it. The flask was set under nitrogen atmosphere and maintained at 80°C. for 2 hours. After the treatment, the fabric was washed with anaqueous soap solution at 60° C. three times (concentration 0.1 wt % anda liquor ratio 1:500). After drying, the water absorption of thenon-woven treated fabric examined by “Water absorption test 1” was2310%. That of an untreated non-woven fabric was 350%. The weightincrease of the specimen after the hydrophilic treatment was 4%. Thewater absorption property of the material prepared by the Aspect 4 ishigher than that by the Aspect 1 (the treatment by the Aspect 1 gave awater absorption of about 1400%) and it gave a large water absorptionrate and a durable water absorption property. The improved non-wovenfabric is preferably available for a wiper for cleansing/wiping (asubstitute for scrubbing cloth). Ten sheets of the hydrophilic fabricwhich was absorbing water (a water absorption, about 2000%) weresuperposed and they were equipped to a cleaning mop. The mop was usedfor cleaning a wooden floor. After the use, they were rinsed with waterand used repeatedly. They could be used over ten times.

EXAMPLE 32

Hydrophilic Treatment of Polypropylene Non-woven Fabric 6 by the Methodof Aspect 1 and an Application for Disposable Sanitary Supplies

A polypropylene fabric 6 was treated with ozone for 30 minutes. Then,the ozone-treated specimen was put in a vessel, and 500 ml of water, 300mg of potassium persulfate, 5.0 g of PVA and 50 ml of methanol were putin it. The reaction mixture was maintained at 80° C. for 2 hours withstirring. After the treatment, the fabric was washed with water at roomtemperature and washed with water of 60° C. three times (2000 ml ofwater was used for each washing). The water absorption of the treatedmaterial examined by “Water absorption test 1” was 800 to 1100%.

A model of disposable diaper was prepared as follows: the hydrophilicpolyolefin non-woven fabrics prepared as above was used for an insidecloth, an untreated hydrophobic polyolefin non-woven fabric was used forthe outside cloth, and a water retention agent (water-absorptionpolymers; starch or polyacrylic acid and their derivatives, etc.) wasused as a core material. Namely, an untreated hydrophobic polypropylenenon-woven fabric was put on the bottom, and a water retention polymerwas put on it, and the hydrophilic polyolefin non-woven fabric of thepresent invention was put on the top. When a cup of water was poured onthe diaper model, water was penetrated quickly through the hydrophilicpolyolefin non-woven fabric and absorbed by the water retention agent.Thus, the non-woven fabric improved in the water absorption propertyprepared by the present invention is available for the material fordisposable diapers and sanitary/physiology supplies.

EXAMPLE 33

Improvement of Adhesion Property of Orthodontic Brackets

20 orthodontic brackets (0.622 g) were treated by the method of Aspect 4similarly to Example 28. The treated brackets gave a good adhesionproperty to ceramic materials for teeth with adhesives for teeth.

Industrial Applicability

As mentioned above, various polymeric materials improved by the presentinvention gave an excellent water absorption property and a goodadhesion property with adhesives. In addition, battery separatorsprepared with the polyolefin non-woven fabric improved by the presentinvention gave a high tensile strength, a high electrolytic solutionretention, and excellent alkali resistance and acid resistance. Thus,the battery separators of the present invention can be used for alkalibatteries and acid batteries as excellent separators which gave nochange in the battery performance.

In addition, the polyolefin filter medium improved in hydrophilicity isuseful for the filtration of aqueous solutions. The improved material bythe present invention gives a water absorption property and an excellentadhesion property to synthetic papers; the improvement of printingproperty is also expected. As the adhesion property of many kinds ofpolymeric materials containing carbon fiber is extremely improved,hydrophilic materials available for reinforcing fibers for compositematerials can be obtained by the present invention. The hydrophilicproperty of the other many kinds of polymeric materials is also improvedby the present invention. The absorption property of water-soluble inkby polyolefin-made members of writing materials which was impossible sofar is also improved.

As the water absorption property can be given to polyolefins, polyestersand composite fibers, etc. by the present invention, the improvedmaterials can be used in various kinds of a medical/sanitary/cosmeticsupplies and a textile product for clothing. When hydrophobic polymerfilms are changed to be hydrophilic ones, the adhesion property to theother materials is extremely improved. When a film with water absorptionproperty is stuck to a glass, the glass gives an anti-fog property. Inaddition, when a material for goggles is directly improved to behydrophilic, it gives an anti-fog property. When the adhesion propertyof orthodontic brackets made of polypropylene is improved by the presentinvention, they can be well bonded to dental materials. Thebio-compatibility of medical materials such as vascular grafts,artificial organs, artificial joints, catheters and drainage apparatusescan be improved.

In addition, it is possible that the surface property of various kindsof materials can be improved to give other properties to them, which canprovide a further development in applications. The present invention canimprove an affinity of water-soluble ink, the property of various kindsof medical/sanitary/cosmetic supplies and textile products for clothing,an adhesion property of orthodontic brackets made of polypropylene andthe water wettability and the other physical property of medicalmaterials.

What is claimed is:
 1. A method of modifying a polymeric material forimproving a hydrophilic property, water absorption property or adhesionproperty which comprises: (a) subjecting the polymeric material to anactivation step for introducing a double bond or a functional groupcontaining at least a carbonyl group on the surface of the polymericmaterial to the extent that a trace of the formation of the carbonylgroup is observed from a ratio of about 0.2 or less of an absorbance ataround 1710 cm⁻¹ due to carbonyl groups introduced in the surface ofpolymeric material to an absorbance of the crystalline region notchanged by the activation step by employing a base line method ofinfrared spectroscopy; and (b) treating the activated polymeric materialproduced in said activation step with a hydrophilic polymer in thepresence of a catalyst or an initiator under conditions effective toproduce said modified polymer, wherein the weight increase of thetreated polymeric material is less than 5 wt %.
 2. The method ofmodifying a polymeric material according to claim 1 further comprisingthe step of monomer grafting in the presence or absence of a catalyst oran initiator under conditions effective to produce said modified polymerafter step (b).
 3. The method according to claim 2, wherein said monomeris a compound having a carbon-carbon double bond.
 4. The methodaccording to claim 3, wherein said monomer is at least one of themonomers selected from the group consisting of acrylic acid, methacrylicacid, vinyl acetate, 2-butene acid, ethylene sulfonic acid, hydroxyalkylacrylate, hydroxyalkyl methacrylate, acryl amide, vinyl pyridine, vinylpyrrolidone, vinyl carbazole, maleic anhydride and pyromelliticdianhydride.
 5. The method according to claim 2, wherein said step ofmonomer grafting is carried out by any one of or both of the followingtwo methods: (1) heating in the presence of catalysts or initiators and(2) UV irradiation in the presence or absence of catalysts, initiatorsor photo-sensitizers.
 6. The method according to claim 2, wherein saidinitiators are at least one of peroxides, cerium ammonium nitrate (IV)or persulfates.
 7. The method of modifying a polymeric materialaccording to claim 1, further comprising the step of a solvent-treatmentprior to the activation step (a), wherein the polymeric material isdipped in a solvent for about 1 minute to 60 minutes at a temperature ofabout 60° C. or less, and a weight increase of the polymeric material is10% or less of the original weight.
 8. The method of modifying apolymeric material according to claim 1, further comprising the step ofa solvent-treatment prior to the activation step (a) and a step ofmonomer grafting after step (b), wherein in the solvent-treatment thepolymeric material is dipped in a solvent for about 1 minute to 60minutes at a temperature to about 60° C., and a weight increase of thepolymeric material is up to 10% of the original weight.
 9. The methodaccording to claim 8, wherein said monomer is a compound having acarbon-carbon double bond.
 10. The method according to claim 9, whereinsaid monomer is at least one of the monomers selected from the groupconsisting of acrylic acid, methacrylic acid, vinyl acetate, 2-buteneacid, ethylene sulfonic acid, hydroxyalkyl acrylate, hydroxyalkylmethacrylate, acryl amide, vinyl pyridine, vinyl pyrrolidone, vinylcarbazole, maleic anhydride and pyromellitic dianhydride.
 11. The methodaccording to claim 8, wherein said step of monomer grafting is carriedout by any one of or both of the following two methods: (1) heating inthe presence of catalysts or initiators and (2) UV irradiation in thepresence or absence of catalysts, initiators or photo-sensitizers. 12.The method according to claim 1, wherein said polymeric material is ahomopolymer or copolymer of one or more compounds selected from thegroup consisting of: olefins, vinyl compounds except olefins, vinylidenecompounds, polyesters, polyamides, polyimides, polyurethanes,polybenzoates, poly(benzoxazole)s, poly(benzthiazole)s,poly-(p-phenylene benzbisoxazole)s, poly-(p-phenylenebenzbis-thiazole)s, poly(alkyl-p-hydroxybenzoate)s,poly(benzimidazole)s, carbonized polymeric materials, polyphenols,cellulose acetate, regenerated cellulose, vinylon, polychlal, casein,wool, silk, hemp, ramie, and jute.
 13. The method according to claim 1,wherein said polymeric material is in the form of any one of fibers,woven fabrics, knitted webs, non-woven fabrics, plates, rods, films,sheets, porous films, members or parts of molded materials in a givenshape or composite materials with other materials.
 14. The methodaccording to claim 1, wherein said activation-treatment is at least oneof the treatments selected from the group consisting of an ozonetreatment, a plasma treatment, a UV irradiation treatment and a highvoltage electric discharge treatment.
 15. The method according to claim1, wherein said hydrophilic polymer is at least one member selected fromthe group consisting of polyvinyl alcohol, carboxymethylcellulose,poly(hydroxy-ethyl methacrylate), poly-α-hydroxy vinylalcohol,polyacrylic acid, polyvinyl pyrrolidone, polyalkylene glycols, starche,silk fibroin, sericin, agar, gelatin, egg white and sodium arginate. 16.The method according to claim 1, wherein said initiators are at leastone of peroxides, cerium ammonium nitrate (IV) or persulfates. 17.Writing materials containing modified polymeric materials obtained bythe method according to claim
 1. 18. Synthetic papers made of modifiedpolymeric materials obtained by the method according to claim
 1. 19.Orthodontic brackets containing modified polymeric materials obtained bythe method according to claim 1.